CLASSES

Selective Serotonin Reuptake Inhibitor Antidepressants, SSRIs

BOXED WARNING

Paroxetine is not FDA-approved for use in children and adolescents less than 18 years of age. Three well-controlled trials have shown that paroxetine is no more effective than placebo for the treatment of depression in pediatric patients. In a pooled analysis of placebo-controlled trials of antidepressants (n = 4,500 pediatrics and 77,000 adults), there was an increased risk for suicidal thoughts and behaviors in patients 24 years of age and younger receiving an antidepressant versus placebo, with considerable variation in the risk of suicidality among drugs. The difference in absolute risk of suicidal thoughts and behaviors across different indications was highest in those with major depression. No suicides occurred in any of the pediatric trials. Data from a cohort of 36,842 children (age range of 6 to 18 years) suggested those who use multiple antidepressants have a higher risk of suicide behavior, most likely a result of increased severity of depression rather than drug effect. In a meta-analysis conducted by the manufacturer in adult patients with and without psychiatric disorders, a higher frequency of suicidal behavior occurred in young adults and adults treated with paroxetine compared with placebo. The need for an antidepressant in children or adolescents for any use must be weighed against the risk of suicidality; it is unknown if this risk extends to long-term use. All patients should be monitored for symptom worsening or suicidality, especially at treatment initiation or after dose changes. Caregivers and/or patients should immediately notify the prescriber of changes in behavior or suicidal ideation. The potential for growth inhibition in pediatric patients should be monitored during SSRI therapy; monitor height and weight periodically. Data are inadequate to determine whether the chronic use of SSRIs causes long-term growth inhibition; however, decreased weight gain has been observed in children and adolescents receiving SSRIs. The mechanism of growth inhibition in children may be due to the suppression of growth hormone secretion, which is known to occur in adults taking SSRIs.

DEA CLASS

Rx

DESCRIPTION

Oral selective serotonin reuptake inhibitor (SSRI) antidepressant
Indicated for depression, OCD, social anxiety, generalized anxiety disorder, panic disorder, PTSD, premenstrual dysphoric disorder, and menopausal hot flashed in adults
Do not use during pregnancy; increased risk of suicidality during treatment initiation in pediatric and young adult patients

COMMON BRAND NAMES

Brisdelle, Paxil, Paxil CR, Pexeva

HOW SUPPLIED

Brisdelle/Paroxetine Oral Cap: 7.5mg
Paroxetine/Paroxetine Hydrochloride/Paxil CR Oral Tab ER: 12.5mg, 25mg, 37.5mg
Paroxetine/Paroxetine Hydrochloride/Paxil Oral Susp: 5mL, 10mg
Paroxetine/Paroxetine Hydrochloride/Paxil/Pexeva Oral Tab: 10mg, 20mg, 30mg, 40mg

DOSAGE & INDICATIONS

†Indicates off-label use

MAXIMUM DOSAGE

60 mg/day PO for immediate-release formulation; 75 mg/day PO for controlled-release formulation.

40 mg/day PO for immediate-release formulation; 50 mg/day PO for controlled-release formulation.

Safety and efficacy have not been established; however, doses up to 50 mg/day PO have been used off-label for anxiety disorders.

7 to 12 years: Safety and efficacy have not been established; however, doses up to 50 mg/day PO have been used off-label for anxiety disorders.
1 to 6 years: Safety and efficacy have not been established.

Safety and efficacy have not been established.

Safety and efficacy have not been established.

DOSING CONSIDERATIONS

Immediate-release dosage forms (i.e., Paxil, Pexeva): Initially, 10 mg/day PO in adults; final adult dosage should not exceed 40 mg/day PO. There are no guidelines available for pediatric patients.
 
Immediate-release 7.5 mg capsules (i.e., Brisdelle): No dose adjustment is considered necessary in patients with hepatic impairment.
 
Controlled-release tablets (Paxil CR): The initial dose is 12.5 mg/day PO in adults, with final adult dosage not to exceed 50 mg/day PO, regardless of indication. There are no guidelines available for pediatric patients.

Patients with renal impairment receiving immediate-release 7.5 mg capsules (i.e., Brisdelle): No dosage adjustment is considered necessary.
 
Patients with renal impairment receiving immediate-release dosage forms including Paxil or Pexeva:
CrCl 30—60 ml/min: Dosage should be modified depending on clinical response and degree of renal impairment, but no quantitative recommendations are available. Lower doses may be needed.
CrCl < 30 ml/min: Initially, 10 mg/day PO in adults; final adult dosage should not exceed 40 mg/day PO. There are no guidelines available for pediatric patients.
 
Patients with severe renal impairment receiving controlled-release dosage forms including Paxil CR:
The initial dose is 12.5 mg/day PO in adults, with final adult dosage not to exceed 50 mg/day PO, regardless of indication. There are no guidelines available for pediatric patients.
 
Intermittent hemodialysis
See dosage for patients with CrCl < 30 ml/min. Dosage adjustments are not necessary in patients receiving the Brisdelle brand. Paroxetine is unlikely to be significantly removed by hemodialysis given its large volume of distribution.

ADMINISTRATION

Administer as a single dose, usually in the morning. May be administered without regard to meals, however, food may minimize GI adverse effects.

STORAGE

Brisdelle:
- Avoid excessive humidity
- Protect from light
- Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
Paxil:
- Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
Paxil CR:
- Store at 77 degrees F; excursions permitted to 59-86 degrees F
Pexeva:
- Avoid excessive humidity
- Store at 77 degrees F; excursions permitted to 59-86 degrees F

CONTRAINDICATIONS / PRECAUTIONS

Paroxetine is contraindicated in those patients with a hypersensitivity to paroxetine or any of the formulation components.

Avoid abrupt discontinuation of any SSRI, like paroxetine, if possible. Gradual tapering is recommended during discontinuation of any SSRI to decrease or prevent the occurrence of potential discontinuation symptoms. The product labeling offers some guidance to taper paroxetine prior to discontinuation to limit withdrawal-type effects. The taper phase regimen used in some clinical trials of paroxetine involved an incremental decrease in the daily dose by 10 mg/day at weekly intervals. When a daily dose of 20 mg/day was reached, this dose was continued for 1 week before treatment was stopped. In controlled trials of paroxetine CR, patients receiving 37.5 mg/day underwent an incremental decrease in the daily dose by 12.5 mg/day for 1 week before treatment was stopped. For patients receiving 12.5 or 25 mg/day, treatment was stopped without a taper. Adverse events were reported in some patients, even with this gradual taper regimen. Patients should be monitored when discontinuing treatment, regardless of the indication for which the SSRI is being prescribed. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, continue decreasing the dose but at a more gradual rate. When used for hot flashes at a dose of 7.5 mg/day, a taper during discontinuation has not been recommended.

The use of antidepressants has been associated with the precipitation of mania or hypomania in susceptible individuals. If a patient develops manic symptoms, paroxetine should be withheld, and appropriate therapy initiated to treat the manic symptoms. Depression may also be the presenting symptom of a mixed/manic episode of bipolar disorder. Patients should be adequately screened for bipolar disorder prior to initiating an antidepressant. Such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression. Patients with depression or comorbid depression in the setting of other psychiatric illness being treated with antidepressants should be observed for clinical worsening and suicidality, especially during the initial few months of a course of drug therapy, or at times of dose changes. Caregivers should be advised to closely observe the patient on a daily basis and to communicate immediately with the prescriber the emergence of agitation, irritability, unusual changes in behavior, or emergence of suicidality.

Paroxetine is not FDA-approved for use in children and adolescents less than 18 years of age. Three well-controlled trials have shown that paroxetine is no more effective than placebo for the treatment of depression in pediatric patients. In a pooled analysis of placebo-controlled trials of antidepressants (n = 4,500 pediatrics and 77,000 adults), there was an increased risk for suicidal thoughts and behaviors in patients 24 years of age and younger receiving an antidepressant versus placebo, with considerable variation in the risk of suicidality among drugs. The difference in absolute risk of suicidal thoughts and behaviors across different indications was highest in those with major depression. No suicides occurred in any of the pediatric trials. Data from a cohort of 36,842 children (age range of 6 to 18 years) suggested those who use multiple antidepressants have a higher risk of suicide behavior, most likely a result of increased severity of depression rather than drug effect. In a meta-analysis conducted by the manufacturer in adult patients with and without psychiatric disorders, a higher frequency of suicidal behavior occurred in young adults and adults treated with paroxetine compared with placebo. The need for an antidepressant in children or adolescents for any use must be weighed against the risk of suicidality; it is unknown if this risk extends to long-term use. All patients should be monitored for symptom worsening or suicidality, especially at treatment initiation or after dose changes. Caregivers and/or patients should immediately notify the prescriber of changes in behavior or suicidal ideation. The potential for growth inhibition in pediatric patients should be monitored during SSRI therapy; monitor height and weight periodically. Data are inadequate to determine whether the chronic use of SSRIs causes long-term growth inhibition; however, decreased weight gain has been observed in children and adolescents receiving SSRIs. The mechanism of growth inhibition in children may be due to the suppression of growth hormone secretion, which is known to occur in adults taking SSRIs.

Concomitant use of MAOI therapy with paroxetine or within 14 days of stopping treatment with paroxetine is contraindicated because of an increased risk of serotonin syndrome. The use of paroxetine within 14 days of stopping MAOI therapy is also contraindicated. Starting paroxetine in a patient who is being treated with linezolid or intravenous methylene blue, both of which inhibit monoamine oxidase, is also contraindicated because of an increased risk of serotonin syndrome. Starting paroxetine in a patient being treated with an MAOI such as linezolid or methylene blue is also contraindicated; however, there may be circumstances when it is necessary to initiate treatment with a MAOI such as linezolid or methylene blue in a patient taking paroxetine. If acceptable alternatives are not available and benefits are judged to outweigh the risks of serotonin syndrome, paroxetine should be promptly discontinued before initiating treatment with the MAOI. Monitor the patient closely for symptoms of serotonin syndrome for 2 weeks or until 24 hours after the last dose of MAOI, whichever comes first. Therapy with paroxetine may be resumed 24 hours after the last dose of MAOI. The development of a potentially life-threatening serotonin syndrome has been reported with the use of SSRIs such as paroxetine alone, but particularly with concomitant use of other serotonergic drugs. If concomitant use of paroxetine with certain other serotonergic drugs (i.e., triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, buspirone, tryptophan, amphetamines, and St. John’s Wort) is clinically warranted, be aware of a potential increased risk for serotonin syndrome, particularly during treatment initiation and dose increases. Treatment with paroxetine and any concomitant serotonergic agents should be discontinued immediately if the above events occur and supportive symptomatic treatment should be initiated.

Paroxetine should be used with caution in patients with a history of seizure disorder. Seizures have been reported rarely in patients taking SSRIs; however, they have occurred primarily in cases of overdose. Paroxetine's effects during electroconvulsive therapy (ECT) have not been evaluated in clinical studies to date.

Selective serotonin reuptake inhibitors (SSRIs), like paroxetine, may cause hyponatremia, which is frequently the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). In some cases, serum sodium levels less than 110 mmol/L have been reported; however, the adverse effect appeared reversible upon discontinuation of the causative SSRI. Older patients (65 years of age or more), those receiving diuretics or prone to dehydration, and those who are otherwise volume depleted (e.g., hypovolemia) appear to be at greatest risk. Hyponatremia may manifest as headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness which may result in falls. Severe manifestations include hallucinations, syncope, seizure, coma, respiratory arrest, and death. Symptomatic hyponatremia may require discontinuation of the SSRI, as well as implementation of the appropriate medical interventions.

Paroxetine should be used with caution in patients with severe renal impairment or renal failure because paroxetine clearance is reduced. Specific dosage adjustments are recommended in adult patients with severe renal impairment (creatinine clearance less than 30 mL/minute). A lower starting dose should be used in patients receiving most paroxetine formulations. The exception is those patients receiving the the 7.5 mg dose for menopause (e.g., Brisdelle) for which no dose adjustment is considered necessary. Quantitative guidelines are not available for pediatric patients.

Paroxetine should be used cautiously in patients with hepatic disease. Adult patients with severe hepatic impairment have about a 2-fold increase in plasma concentrations of paroxetine compared to patients without hepatic impairment. Specific dosage adjustments are recommended in adult patients with severe hepatic impairment receiving all formulations except the 7.5 mg dose for menopause (e.g., Brisdelle) for which no dose adjustment is considered necessary. Quantitative guidelines are not available for pediatric patients.

Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion. Paroxetine and other SSRIs may increase the risk of bleeding events. Concomitant use of aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), warfarin, and other anticoagulant therapy may add to this risk. Case reports and epidemiological studies (case-control and cohort design) have demonstrated an association between use of drugs that interfere with serotonin reuptake and the occurrence of gastrointestinal bleeding. Bleeding events related to SSRIs and SNRIs use have ranged from ecchymoses, hematomas, epistaxis, and petechiae to life-threatening hemorrhages. Patients and practitioners should be cautioned about the risk of bleeding associated with the concomitant use of paroxetine and NSAIDs, aspirin, anticoagulants, or other drugs that affect coagulation, such as thrombolytic therapy. Monitor patients for signs and symptoms of bleeding.

Although clinical trial data indicate that paroxetine is not associated with the development of clinically significant ECG abnormalities in adults, the use of paroxetine has not been systematically evaluated in patients with a recent history of myocardial infarction or unstable cardiac disease. Evaluation of electrocardiograms (ECGs) of 682 patients who received paroxetine in double-blind, placebo-controlled trials, however, did not indicate that paroxetine is associated with the development of significant ECG abnormalities. Paroxetine should be used with caution in patients with congenital heart disease or in those who are taking other medications concomitantly that might result in drug interactions. For example, QT prolongation, tachycardias, and other side effects have been reported in children taking clomipramine in combination with paroxetine for the treatment of obsessive-compulsive disorder (OCD), or in adult patients taking paroxetine (a CYP2D6 inhibitor) along with medications known to prolong the QT interval that are metabolized by CYP2D6. Additional monitoring may be necessary, especially when a patient receives combined treatments.

Use selective serotonin reuptake inhibitors (SSRIs), including paroxetine, with caution in patients with osteoporosis. Epidemiological studies on bone fracture risk following exposure to SSRIs have reported an association between SSRI treatment and bone fractures. It is unknown to what extent fracture risk is directly attributable to SSRI treatment. If a paroxetine-treated patient presents with unexplained bone pain, point tenderness, swelling, or bruising, consider the possibility of a fragility fracture. Patients at risk for osteoporosis, such as postmenopausal females, may benefit from more frequent monitoring of bone density during long-term use of an SSRI. 

Caution is recommended when prescribing paroxetine to patients with closed-angle glaucoma. The pupillary dilation that can occur with antidepressants may precipitate a closed-angle glaucoma attack in patients with anatomically narrow angles who do not have a patent iridectomy. An acute attack of closed-angle glaucoma is considered a medical emergency because the increased intraocular pressure is rapid and severe, and may quickly result in blindness if left untreated. Patients may wish to be examined to determine whether they are susceptible to angle closure, and have a prophylactic procedure (e.g., iridectomy), if they are susceptible.

The use of paroxetine or other SSRIs has been associated with the development of akathisia, which is characterized by an inner sense of restlessness and psychomotor agitation such as an inability to sit or stand still usually associated with subjective distress. This is most likely to occur within the first few weeks of treatment.

Decreased appetite and weight loss have been observed during administration of SSRIs. Therefore, caution is advisable when administering paroxetine to patients with anorexia nervosa or other conditions where weight loss is undesirable.

Because any psychoactive drug may impair judgment, thinking, or motor skills, patients should use caution when driving or operating machinery, until they are reasonably certain that paroxetine does not affect them adversely. Although paroxetine has not been shown to increase the impairment of mental and motor skills caused by alcohol, patients should be advised to avoid ethanol ingestion while taking paroxetine.

Sexual dysfunction can occur in individuals taking paroxetine. For males, these effects may present as ejaculatory failure or delay, decreased libido, and/or erectile dysfunction. Females may experience decreased libido and delayed or absent orgasm. Prescribers should discuss sexual function prior to initiating treatment with paroxetine and throughout treatment and obtain a detailed history and timeline of any changes in sexual function to determine whether the changes are medication-related or may be attributed to the underlying psychiatric disorder. Clinicians should also discuss management strategies and treatment options with patients.

All formulations of paroxetine may cause fetal harm during human pregnancy; the paroxetine capsule for treatment of menopause (e.g., Brisdelle) is contraindicated for use during pregnancy because menopausal vasomotor symptoms do not occur during pregnancy and paroxetine can cause fetal harm. Unless other treatment options are not available, do not initiate paroxetine during the first trimester of pregnancy or in women who plan to become pregnant in the near future. The FDA is evaluating data to better characterize the risk of congenital malformations resulting from infant exposure to paroxetine during pregnancy. Exposure in the first trimester may increase the risk for congenital malformations, particularly cardiac malformations. A retrospective, epidemiologic study derived from the Swedish National Registry, comprised of 6896 women prescribed antidepressants in early pregnancy (5,123 of these women exposed to SSRIs; 815 to paroxetine) suggests an increased risk of cardiovascular malformations, primarily ventricular (VSDs) and atrial (ASDs) septal defects in those with exposure to paroxetine. This increased risk was seen compared to the entire registry population (OR 1.8; 95% CI 1.1 to 2.8). The rate of cardiovascular malformations following paroxetine exposure was 2% vs. 1% in the entire registry population; however, there was no increase in the overall risk for congenital malformations in either group. In another retrospective, cohort study (a US health insurance claims database), evaluating infant outcomes in those whose mothers received antidepressants in the first trimester (n = 5,956 total ; 815 for paroxetine), a 1.5-fold elevated risk for cardiac malformations and a 1.8-fold elevated risk for overall congenital malformations was seen in the paroxetine group compared to the group that received other antidepressants in the first trimester (OR 1.5; 95% CI 0.8 to 2.9). The prevalence of cardiac malformations when drug was received in the first trimester was 1.5% for paroxetine and 1% for other antidepressants. Nine out of 12 newborns with cardiac malformations whose mothers received paroxetine in the first trimester had VSDs. Unlike the first study, there was an increased risk of overall major congenital malformations (inclusive of the cardiovascular defects) for paroxetine compared to other antidepressants (OR 1.8; 95% CI 1.2 to 2.8). The prevalence of all congenital malformations following first trimester exposure was 4% for paroxetine vs. 2% for other antidepressants. Results from 2 large case-control studies (each with more than 9,000 birth defect cases and more than 4,000 controls) showed a 2- to 3-fold increased risk of right ventricular outflow tract obstructions from infant exposures to paroxetine in utero during the first trimester of pregnancy, with 7 exposed in one study (OR 2.5; 95% CI, 1 to 6), and 6 exposed in the other study (OR 3.3; 95% CI 1.3 to 8.8). All of these studies were limited to first trimester exposure only, therefore the risk of fetal exposure to paroxetine in the second and third trimesters is not known. A prospective, cohort study was conducted to evaluate the outcome of newborns born to 267 women who took an SSRI during pregnancy (of whom 97 took paroxetine). Compared with a neonatal control group, SSRI-exposed neonates had similar rates of major malformation, spontaneous and elective abortion, and stillbirth. Mean birth weight and gestational age were similar among the two groups of neonates. In animal studies, SSRIs appear to downregulate serotonin receptors in the fetal cortex; the changes are present for a period of time after birth but the effect on neurological development is uncertain; the applicability of these findings to humans is also unknown. A neonatal abstinence syndrome has been reported at birth following in utero paroxetine exposure; exposed neonates may need to be monitored for associated symptoms. A cohort study of 55 women revealed that 22% (12 of 55) of neonates exposed to paroxetine in the third trimester had complications requiring treatment or extended hospitalization vs. 6% in comparison groups. Post-marketing reports indicate that premature births have occurred in pregnant women receiving paroxetine or other SSRIs. Additionally, epidemiologic reports suggest a possible association between maternal use of SSRIs after 20 weeks gestation and the development of persistent pulmonary hypertension (PPHN) of the newborn. More recent retrospective studies have not shown an increased risk of PPHN with SSRI exposure. In December 2011, the FDA issued a safety announcement stating that based on conflicting data, an increased risk of PPHN from SSRI exposure cannot be determined. The FDA advises that healthcare professionals should not alter their current practice of treating depression in pregnancy at this time. Increasing evidence suggests an association between antidepressant use during pregnancy and a subsequent diagnosis of autism spectrum disorder (ASD) in the offspring. In two separate population based case-control studies, an approximate 2-fold increased risk of autism spectrum disorder was observed. One study found the increased risk was associated only with SSRI use, while the other study found an increased risk associated with use of SSRIs and tricyclic antidepressants. Providers should inform women receiving paroxetine to the potential fetal risk if they should become pregnant or are currently in their first trimester. Discontinuing paroxetine and switching to another antidepressant should be considered when possible for these patients. Women who are pregnant, or are planning a pregnancy, and currently taking paroxetine should consult with their physician about whether to continue taking it. A prospective study of pregnant women receiving antidepressant treatment found that only 26% of those maintained on their antidepressant had relapsed versus 68% of those who had discontinued their medication. In individual cases, the benefits of continuing paroxetine may outweigh the potential risk to the fetus. The effect of SSRIs on labor and delivery in humans is unknown. There is a pregnancy exposure registry that monitors outcomes in pregnant patients exposed to paroxetine; information about the registry can be obtained at womensmentalhealth.org/research/pregnancyregistry or by calling 1-866-961-2388.

Paroxetine should be administered to a breast-feeding mother with caution. In one small trial, mothers ingested up to 50 mg/day PO of paroxetine for more than 10 days. Paroxetine was excreted into the breast milk, but at low concentrations (less than 2 ng/mL). None of the breast-fed infants had detectable serum concentrations and none experienced adverse effects from the medication. Other SSRIs (e.g., fluoxetine) are excreted in breast milk and have been reported to increase infant irritability. The long-term effects of paroxetine on a breast-feeding infant are unknown. A pooled analysis found that maternal use of paroxetine, along with nortriptyline and sertraline, usually produced undetectable or low drug concentrations in infant serum and, therefore, may be the preferred antidepressants in breast-feeding mothers. Consider the benefits of breast-feeding, the risk of potential drug exposure, and the risk of an untreated or inadequately treated condition.

Paroxetine should be used with caution in geriatric patients. Pharmacokinetic data indicate that paroxetine clearance is reduced in the elderly. Although no difference in safety has been recorded, slow titration of dosage is recommended in the elderly. SSRIs may cause hyponatremia and syndrome of inappropriate antidiuretic hormone secretion (SIADH); elderly patients appear to be at greater risk. Paroxetine also exhibits anticholinergic activity. These effects may be additive with other anticholinergic medications in any patient, but the geriatric adult may be more susceptible.[64280] According to the Beers Criteria, paroxetine is considered a potentially inappropriate medication (PIM) in geriatric patients; avoid use due to the potential for orthostatic hypotension, anticholinergic effects (e.g., constipation, urinary difficulties, blurred vision, dry mouth, delirium), or sedation. Avoid medications with anticholinergic properties in geriatric patients with the following conditions due to the potential for symptom exacerbation or adverse effects: dementia/cognitive impairment (adverse CNS effects), delirium/high risk of delirium (new-onset or worsening delirium), or lower urinary tract symptoms/benign prostatic hyperplasia in men (urinary retention or hesitancy). The Panel also recommends avoiding paroxetine in geriatric patients with a history of falls or fractures unless no other alternatives are available since SSRIs have the potential to cause ataxia, impaired psychomotor function, syncope, and additional falls; if paroxetine must be used, consider reducing use of other CNS-active medications that increase the risk of falls and fractures and implement other strategies to reduce fall risk. SSRIs can cause or exacerbate hyponatremia and SIADH, and sodium levels should be closely monitored when starting or changing dosages in older adults.[63923] The federal Omnibus Budget Reconciliation Act (OBRA) regulates the use of antidepressants in residents of long-term care facilities; the duration of therapy should be in accordance with pertinent literature and clinical practice guidelines. All residents being treated for depression with any antidepressant should be monitored closely for worsening of depression and suicidal behavior or thinking, especially during initiation of therapy and during dose changes. Antidepressants may cause side effects that can increase the risk of falls. Paroxetine has significant anticholinergic properties that may problematic in the elderly. Before discontinuation, SSRIs may need a taper to avoid a withdrawal syndrome. Review the continued need of an antidepressant at least quarterly, and document the rationale for continuation. When the drug is being used to manage behavior, stabilize mood, or treat a psychiatric disorder, the facility should attempt to taper the medication as outlined in the OBRA guidelines, unless a taper is clinically contraindicated.[60742]

ADVERSE REACTIONS

visual impairment / Early / 1.0-5.0
muscle paralysis / Delayed / 0.1-1.0
seizures / Delayed / 0.1-1.0
bradycardia / Rapid / 0.1-1.0
angioedema / Rapid / 0.1-1.0
anaphylactoid reactions / Rapid / 0.1-1.0
bronchospasm / Rapid / 0.1-1.0
keratoconjunctivitis / Early / 0.1-1.0
pancreatitis / Delayed / 0.1-1.0
proteinuria / Delayed / 0.1-1.0
peptic ulcer / Delayed / 0-0.1
hematemesis / Delayed / 0-0.1
GI obstruction / Delayed / 0-0.1
ileus / Delayed / 0-0.1
akinesia / Delayed / 0-0.1
torticollis / Delayed / 0-0.1
coma / Early / 0-0.1
myelitis / Delayed / 0-0.1
myocardial infarction / Delayed / 0-0.1
stroke / Early / 0-0.1
atrial fibrillation / Early / 0-0.1
heart failure / Delayed / 0-0.1
pulmonary embolism / Delayed / 0-0.1
thrombosis / Delayed / 0-0.1
erythema nodosum / Delayed / 0-0.1
erythema multiforme / Delayed / 0-0.1
exfoliative dermatitis / Delayed / 0-0.1
pulmonary fibrosis / Delayed / 0-0.1
pulmonary edema / Early / 0-0.1
hearing loss / Delayed / 0-0.1
retinal hemorrhage / Delayed / 0-0.1
ocular hypertension / Delayed / 0-0.1
ocular hemorrhage / Delayed / 0-0.1
oliguria / Early / 0-0.1
epididymitis / Delayed / 0-0.1
hyperkalemia / Delayed / 0-0.1
laryngospasm / Rapid / Incidence not known
Guillain-Barre syndrome / Delayed / Incidence not known
SIADH / Delayed / Incidence not known
vasculitis / Delayed / Incidence not known
agranulocytosis / Delayed / Incidence not known
aplastic anemia / Delayed / Incidence not known
GI bleeding / Delayed / Incidence not known
pancytopenia / Delayed / Incidence not known
hemolytic anemia / Delayed / Incidence not known
ventricular fibrillation / Early / Incidence not known
torsade de pointes / Rapid / Incidence not known
ventricular tachycardia / Early / Incidence not known
pulmonary hypertension / Delayed / Incidence not known
toxic epidermal necrolysis / Delayed / Incidence not known
Stevens-Johnson syndrome / Delayed / Incidence not known
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) / Delayed / Incidence not known
optic neuritis / Delayed / Incidence not known
hepatic necrosis / Delayed / Incidence not known
porphyria / Delayed / Incidence not known
renal failure (unspecified) / Delayed / Incidence not known
serotonin syndrome / Delayed / Incidence not known
bone fractures / Delayed / Incidence not known
teratogenesis / Delayed / Incidence not known
neonatal abstinence syndrome / Early / Incidence not known
persistent pulmonary hypertension of the newborn / Delayed / Incidence not known

ejaculation dysfunction / Delayed / 13.0-28.0
constipation / Delayed / 5.0-16.0
impotence (erectile dysfunction) / Delayed / 4.0-10.0
peripheral vasodilation / Rapid / 2.0-4.0
blurred vision / Early / 2.0-4.0
hypertonia / Delayed / 0.1-3.0
myoclonia / Delayed / 1.0-3.0
chest pain (unspecified) / Early / 1.0-3.0
palpitations / Early / 2.0-3.0
dysuria / Early / 0.1-3.0
memory impairment / Delayed / 2.0-2.0
amnesia / Delayed / 0.1-2.0
hypertension / Early / 1.0-2.0
sinus tachycardia / Rapid / 1.0-2.0
myopathy / Delayed / 0-2.0
teeth grinding (bruxism) / Delayed / 0.1-1.0
stomatitis / Delayed / 0.1-1.0
colitis / Delayed / 0-1.0
dysphagia / Delayed / 0.1-1.0
melena / Delayed / 0-1.0
gastritis / Delayed / 0.1-1.0
hemorrhoids / Delayed / 0.1-1.0
dyskinesia / Delayed / 0.1-1.0
dystonic reaction / Delayed / 0.1-1.0
nystagmus / Delayed / 0-1.0
confusion / Early / 1.0-1.0
migraine / Early / 0.1-1.0
ataxia / Delayed / 0-1.0
neuropathic pain / Delayed / 0-1.0
lymphadenopathy / Delayed / 0.1-1.0
anemia / Delayed / 0.1-1.0
leukopenia / Delayed / 1.0-1.0
eosinophilia / Delayed / 0.1-1.0
hematoma / Early / 0.1-1.0
orthostatic hypotension / Delayed / 0.1-1.0
hypotension / Rapid / 0.1-1.0
supraventricular tachycardia (SVT) / Early / 0.1-1.0
angina / Early / 0-1.0
edema / Delayed / 0.1-1.0
contact dermatitis / Delayed / 0.1-1.0
atopic dermatitis / Delayed / 1.0-1.0
dyspnea / Early / 0.1-1.0
conjunctivitis / Delayed / 0.1-1.0
elevated hepatic enzymes / Delayed / 0.1-1.0
vaginitis / Delayed / 0.1-1.0
urinary retention / Early / 0.1-1.0
pyuria / Delayed / 0.1-1.0
urinary incontinence / Early / 0.1-1.0
cystitis / Delayed / 0.1-1.0
myasthenia / Delayed / 0-1.0
peripheral edema / Delayed / 0.1-1.0
oral ulceration / Delayed / 0-0.1
sialadenitis / Delayed / 0-0.1
gingival hyperplasia / Delayed / 0-0.1
glossitis / Early / 0-0.1
cholelithiasis / Delayed / 0-0.1
fecal incontinence / Early / 0-0.1
esophagitis / Delayed / 0-0.1
choreoathetosis / Delayed / 0-0.1
dysarthria / Delayed / 0-0.1
trismus / Delayed / 0-0.1
meningitis / Delayed / 0-0.1
hyperreflexia / Delayed / 0-0.1
aphasia / Delayed / 0-0.1
hyperalgesia / Delayed / 0-0.1
neuritis / Delayed / 0-0.1
hyponatremia / Delayed / 0-0.1
thrombocytopenia / Delayed / 0-0.1
lymphopenia / Delayed / 0-0.1
prolonged bleeding time / Delayed / 0-0.1
lymphocytosis / Delayed / 0-0.1
bundle-branch block / Early / 0-0.1
phlebitis / Rapid / 0-0.1
candidiasis / Delayed / 0-0.1
furunculosis / Delayed / 0-0.1
skin ulcer / Delayed / 0-0.1
bullous rash / Early / 0-0.1
hemoptysis / Delayed / 0-0.1
dysphonia / Delayed / 0-0.1
amblyopia / Delayed / 0-0.1
blepharitis / Early / 0-0.1
hyperacusis / Delayed / 0-0.1
cataracts / Delayed / 0-0.1
exophthalmos / Delayed / 0-0.1
photophobia / Early / 0-0.1
hyperbilirubinemia / Delayed / 0-0.1
jaundice / Delayed / 0-0.1
hepatitis / Delayed / 0-0.1
vaginal bleeding / Delayed / 0-0.1
prostatitis / Delayed / 0-0.1
nephrolithiasis / Delayed / 0-0.1
flank pain / Delayed / 0-0.1
tetany / Early / 0-0.1
hypothyroidism / Delayed / 0-0.1
hyperthyroidism / Delayed / 0-0.1
diabetes mellitus / Delayed / 0-0.1
goiter / Delayed / 0-0.1
hyperglycemia / Delayed / 0-0.1
hypoglycemia / Early / 0-0.1
hypercalcemia / Delayed / 0-0.1
hypokalemia / Delayed / 0-0.1
hypercholesterolemia / Delayed / 0-0.1
hypocalcemia / Delayed / 0-0.1
gout / Delayed / 0-0.1
dehydration / Delayed / 0-0.1
hyperphosphatemia / Delayed / 0-0.1
osteoporosis / Delayed / 0-0.1
withdrawal / Early / 0-0.1
akathisia / Delayed / Incidence not known
bleeding / Early / Incidence not known
platelet dysfunction / Delayed / Incidence not known
pneumonitis / Delayed / Incidence not known
hepatomegaly / Delayed / Incidence not known
hyperprolactinemia / Delayed / Incidence not known
priapism / Early / Incidence not known
galactorrhea / Delayed / Incidence not known
hematuria / Delayed / Incidence not known
osteopenia / Delayed / Incidence not known
growth inhibition / Delayed / Incidence not known

headache / Early / 6.3-27.0
nausea / Early / 4.3-26.0
drowsiness / Early / 9.0-24.0
insomnia / Early / 8.0-24.0
asthenia / Delayed / 12.0-22.0
diarrhea / Early / 6.0-18.0
xerostomia / Early / 3.0-18.0
dizziness / Early / 6.0-14.0
libido decrease / Delayed / 3.0-12.0
tremor / Early / 4.0-11.0
hyperhidrosis / Delayed / 6.0-11.0
anorexia / Delayed / 1.0-9.0
orgasm dysfunction / Delayed / 2.0-9.0
sinusitis / Delayed / 4.0-8.0
infection / Delayed / 5.0-8.0
abdominal pain / Early / 3.0-7.0
flatulence / Early / 4.0-6.0
dyspepsia / Early / 2.0-5.0
yawning / Early / 4.0-5.0
dysmenorrhea / Delayed / 1.0-5.0
back pain / Delayed / 3.0-5.0
myalgia / Early / 2.0-5.0
malaise / Early / 0-4.9
fatigue / Early / 0-4.9
lethargy / Early / 0-4.9
appetite stimulation / Delayed / 2.0-4.0
paresthesias / Delayed / 1.0-4.0
abnormal dreams / Early / 1.0-4.0
pharyngitis / Delayed / 1.0-4.0
rhinitis / Early / 3.0-4.0
weight gain / Delayed / 1.0-3.0
vomiting / Early / 2.0-3.0
rash / Early / 2.0-3.0
increased urinary frequency / Early / 2.0-3.0
chills / Rapid / 2.0-2.0
cough / Delayed / 1.0-2.0
fever / Early / 1.0-2.0
dysgeusia / Early / 2.0-2.0
arthralgia / Delayed / 1.0-2.0
gingivitis / Delayed / 0-1.0
dental pain / Delayed / 0.1-1.0
eructation / Early / 0.1-1.0
gastroesophageal reflux / Delayed / 0.1-1.0
weight loss / Delayed / 0.1-1.0
hyperkinesis / Delayed / 0.1-1.0
vertigo / Early / 0.1-1.0
hypoesthesia / Delayed / 0.1-1.0
purpura / Delayed / 0.1-1.0
leukocytosis / Delayed / 0.1-1.0
ecchymosis / Delayed / 0.1-1.0
syncope / Early / 0.1-1.0
photosensitivity / Delayed / 0.1-1.0
acne vulgaris / Delayed / 0.1-1.0
urticaria / Rapid / 0.1-1.0
xerosis / Delayed / 0.1-1.0
alopecia / Delayed / 0.1-1.0
hyperventilation / Early / 0-1.0
laryngitis / Delayed / 0.1-1.0
ocular pain / Early / 0.1-1.0
mydriasis / Early / 0.1-1.0
otalgia / Early / 0.1-1.0
amenorrhea / Delayed / 0.1-1.0
libido increase / Delayed / 0.1-1.0
menorrhagia / Delayed / 0.1-1.0
urinary urgency / Early / 0.1-1.0
polyuria / Early / 0.1-1.0
nocturia / Early / 0-1.0
polydipsia / Early / 0.1-1.0
dental caries / Delayed / 0-0.1
tongue discoloration / Delayed / 0-0.1
hyporeflexia / Delayed / 0-0.1
pallor / Early / 0-0.1
hypothermia / Delayed / 0-0.1
skin discoloration / Delayed / 0-0.1
seborrhea / Delayed / 0-0.1
vesicular rash / Delayed / 0-0.1
maculopapular rash / Early / 0-0.1
hirsutism / Delayed / 0-0.1
hiccups / Early / 0-0.1
diplopia / Early / 0-0.1
parosmia / Delayed / 0-0.1
ptosis / Delayed / 0-0.1
gynecomastia / Delayed / 0-0.1
leukorrhea / Delayed / 0-0.1
mastalgia / Delayed / 0-0.1
breast enlargement / Delayed / 0-0.1
breast discharge / Delayed / 0-0.1
pelvic pain / Delayed / 0-0.1
muscle cramps / Delayed / 0-0.1
pruritus / Rapid / 1.0
tinnitus / Delayed / 1.0
restless legs syndrome (RLS) / Delayed / Incidence not known
petechiae / Delayed / Incidence not known

DRUG INTERACTIONS

Abciximab: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving abciximab. Monitor closely for signs and symptoms of bleeding.
Acetaminophen; Aspirin, ASA; Caffeine: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Acetaminophen; Caffeine; Dihydrocodeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of dihydrocodeine and paroxetine because of the potential risk of serotonin syndrome, reduced dihydrocodeine efficacy, and potential for opioid withdrawal symptoms. Discontinue dihydrocodeine if serotonin syndrome is suspected. It is recommended to avoid this combination when dihydrocodeine is being used for cough. Concomitant use may increase dihydrocodeine plasma concentrations, but decrease the plasma concentration of the active metabolite, dihydromorphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of dihydrocodeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease dihydrocodeine plasma concentrations and increase dihydromorphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Dihydrocodeine is primarily metabolized by CYP2D6 to dihydromorphine, and by CYP3A4. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Acetaminophen; Caffeine; Magnesium Salicylate; Phenyltoloxamine: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. A cohort study in > 26,000 patients found that SSRI use alone increased the risk for serious GI bleed by 3.6-fold; when an SSRI was combined with aspirin the risk was increased by > 5-fold. The absolute risk of GI bleed from concomitant therapy with aspirin and a SSRI was low (20/2640 patients) in this cohort study and the clinician may determine that the combined use of these drugs is appropriate.
Acetaminophen; Caffeine; Phenyltoloxamine; Salicylamide: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. A cohort study in > 26,000 patients found that SSRI use alone increased the risk for serious GI bleed by 3.6-fold; when an SSRI was combined with aspirin the risk was increased by > 5-fold. The absolute risk of GI bleed from concomitant therapy with aspirin and a SSRI was low (20/2640 patients) in this cohort study and the clinician may determine that the combined use of these drugs is appropriate.
Acetaminophen; Chlorpheniramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Chlorpheniramine; Phenylephrine; Phenyltoloxamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Codeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Acetaminophen; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Acetaminophen; Dextromethorphan; Doxylamine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as doxylamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Acetaminophen; Diphenhydramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Hydrocodone: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Acetaminophen; Oxycodone: (Moderate) If concomitant use of oxycodone and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Acetaminophen; Pamabrom; Pyrilamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as pyrilamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Acetaminophen; Pentazocine: (Major) Because of the potential risk and severity of serotonin syndrome reactions, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as pentazocine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome occurs, discontinue the offending agent(s) and institute appropriate therapy.
Alfentanil: (Moderate) If concomitant use of alfentanil and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Almotriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering almotriptan with paroxetine. Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists and selective serotonin reuptake inhibitors (SSRIs). Some patients had used the combination previously without incident when serotonin syndrome occurred. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly after a dose increase of the SSRI or the addition of other serotonergic medications to an existing SSRI regimen. Discontinue paroxetine and almotriptan and initiate symptomatic treatment if serotonin syndrome occurs.
Alprazolam: (Minor) The manufacturer of alprazolam states that in vitro studies suggest paroxetine may inhibit the metabolism of alprazolam via inhibition of CYP3A4. However, paroxetine is typically considered a major inhibitor of CYP2D6, for which alprazolam is not a substrate. The potential for clinical interaction is uncertain. Be alert for any change in psychomotor performance or other benzodiazepine-related side effects when paroxetine is combined with alprazolam.
Alteplase: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving thrombolytic agents. Patients should be closely monitored for signs and symptoms of bleeding when a thrombolytic agent is administered with an SSRI.
Amiodarone: (Minor) Amiodarone inhibits CYP2D6 and may theoretically increase concentrations of other drugs metabolized by this enzyme including paroxetine.
Amitriptyline: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of amitriptyline, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and amitriptyline may exhibit significant anticholinergic effects that may be additive during concurrent use.
Amoxapine: (Moderate) Paroxetine, a potent CYP2D6 inhibitor, may increase the plasma concentrations of the tetracyclic antidepressant amoxapine, which is partially metabolized by CYP2D6. In several cases, symptoms of toxicity, including seizures, have been reported when tricyclic antidepressants were coadministered with a selective serotonin reuptake inhibitor (SSRI). At least one case report exists of a death thought to be due to impaired clearance of the tricyclic antidepressant amitriptyline by fluoxetine. Additive anticholinergic effects are possible. This combination may represent duplicative therapy. Patients receiving amoxapine should be monitored closely for toxicity if paroxetine is added.
Amphetamines: (Moderate) Coadministration of paroxetine and amphetamines may increase the risk for serotonin syndrome or amphetamine-related side effects. At high doses, amphetamines can increase serotonin release, as well as act as serotonin agonists. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome particularly after initiation of therapy, dose increases, or the addition of other serotonergic medications. Discontinue serotonergic agents if serotonin syndrome occurs and implement appropriate medical management. In addition, amphetamines are partially metabolized by CYP2D6 and paroxetine is a strong CYP2D6 inhibitor. Increased systemic exposure to amphetamines from CYP2D6 inhibition may cause increased blood pressure or heart rate, anxiety, insomnia, or other amphetamine-related adverse effects.
Anagrelide: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication (e.g., gastrointestinal bleeding, ecchymoses, epistaxis, hematomas, petechiae, hemorrhage) in patients receiving platelet inhibitors (e.g., cilostazol, clopidogrel, dipyridamole, ticlopidine, platelet glycoprotein IIb/IIIa inhibitors). Patients should be instructed to monitor for signs and symptoms of bleeding while taking an SSRI concurrently with an antiplatelet medication and to promptly report any bleeding events to the practitioner.
Anticholinergics: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Antithrombin III: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like antithrombin III. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Apixaban: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like apixaban. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Ardeparin: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like low molecular weight heparins. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Aripiprazole: (Major) Paroxetine, a potent inhibitor of CYP2D6, may decrease the metabolism of CYP2D6 substrates such as aripiprazole. Decreased metabolism of aripiprazole may lead to adverse effects such as extrapyramidal symptoms, QT prolongation, and torsade de pointes (TdP). The manufacturer of aripiprazole recommends that the oral aripiprazole dose be reduced to one-half of the usual dose when coadministered with strong CYP2D6 inhibitors. Adults receiving 300 mg or 400 mg of Abilify Maintena should have a dose reduction to 200 mg or 300 mg, respectively, during coadministration of a potent CYP2D6 inhibitor if used for more than 14 days. In adults receiving Aristada, the Aristada dose should be reduced to the next lower strength during use of a strong CYP2D6 inhibitor for more than 14 days. For patients receiving 882 mg of Aristada every 6 weeks or 1,064 mg every 2 months, the next lower strength should be 441 mg administered every 4 weeks. No dosage adjustment is necessary in patients taking 441 mg of Aristada, if tolerated. Because aripiprazole is also metabolized by CYP3A4, patients receiving a combination of a CYP3A4 and CYP2D6 inhibitor should have their oral aripiprazole dose reduced to one-quarter (25%) of the usual dose with subsequent adjustments based upon clinical response. Patients receiving a combination of a CYP3A4 and CYP2D6 inhibitor for more than 14 days should have their Abilify Maintena dose reduced from 400 mg/month to 200 mg/month or from 300 mg/month to 160 mg/month, respectively. In adults receiving Aristada 662 mg, 882 mg, or 1,064 mg, combined use of a strong CYP2D6 inhibitor and a strong CYP3A4 inhibitor for more than 14 days should be avoided; no dose adjustment is needed in patients taking 441 mg, if tolerated. Avoid concurrent use of Aristada Initio and strong CYP2D6 inhibitors because the dose of Aristada Initio cannot be modified. Aripiprazole dosage adjustments are not required when aripiprazole is added as adjunctive treatment to antidepressants for major depressive disorder provided that the manufacturer's dosing guidelines for this indication are followed.
Asenapine: (Major) If paroxetine and asenapine are used together, reduce the paroxetine dose by half. Asenapine may enhance the inhibitory effects of paroxetine on its own metabolism; in one study, co-administration of paroxetine and asenapine increased paroxetine exposure by 2-fold compared to that seen during paroxetine use alone. In addition, there may theoretically be an increased risk of QT prolongation and other adverse events associated with asenapine use if the drugs are used together. CYP2D6 plays a minor role in asenapine's metabolism, and paroxetine is a potent CYP2D6 inhibitor. However, because asenapine is metabolized by multiple pathways, a clinically significant interaction is less likely to occur.
Aspirin, ASA: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Butalbital; Caffeine: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Butalbital; Caffeine; Codeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Caffeine: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Caffeine; Dihydrocodeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of dihydrocodeine and paroxetine because of the potential risk of serotonin syndrome, reduced dihydrocodeine efficacy, and potential for opioid withdrawal symptoms. Discontinue dihydrocodeine if serotonin syndrome is suspected. It is recommended to avoid this combination when dihydrocodeine is being used for cough. Concomitant use may increase dihydrocodeine plasma concentrations, but decrease the plasma concentration of the active metabolite, dihydromorphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of dihydrocodeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease dihydrocodeine plasma concentrations and increase dihydromorphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Dihydrocodeine is primarily metabolized by CYP2D6 to dihydromorphine, and by CYP3A4. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Caffeine; Orphenadrine: (Moderate) Additive anticholinergic effects may be seen when drugs with anticholinergic properties, like paroxetine and orphenadrine, are used concomitantly. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Carisoprodol: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Carisoprodol; Codeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Citric Acid; Sodium Bicarbonate: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Dipyridamole: (Moderate) Platelet aggregation may be impaired by SSRIs due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving platelet inhibitors. Monitor for signs and symptoms of bleeding. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Omeprazole: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Oxycodone: (Moderate) If concomitant use of oxycodone and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Aspirin, ASA; Pravastatin: (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Atazanavir; Cobicistat: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of selective serotonin reuptake inhibitors (SSRIs) and cobicistat. Concurrent use may result in elevated SSRI plasma concentrations. Predictions regarding this interaction can be made based on the metabolic pathways of these drugs. All SSRIs are substrates for the hepatic isoenzyme CYP2D6, while citalopram, escitalopram, and sertraline are also substrates for CYP3A4; cobicistat is an inhibitor of both CYP2D6 and CYP3A4.
Atomoxetine: (Major) Dosage reduction of atomoxetine is recommended in patients receiving paroxetine due to the potential for increased atomoxetine exposure and related adverse effects. In children and adolescents up to 70 kg receiving paroxetine, atomoxetine should be initiated at 0.5 mg/kg/day and only increased to the usual target dose of 1.2 mg/kg/day if symptoms fail to improve after 4 weeks and the initial dose is well-tolerated. In children and adolescents over 70 kg and adults receiving paroxetine, atomoxetine should be initiated at 40 mg/day and only increased to the usual target dose of 80 mg/day if symptoms fail to improve after 4 weeks and the initial dose is well-tolerated. Paroxetine is a strong CYP2D6 inhibitor; atomoxetine is a CYP2D6 substrate. Coadministration of a strong CYP2D6 inhibitor and atomoxetine in extensive metabolizers of CYP2D6, increased atomoxetine steady-state plasma concentrations by approximately 6 to 8-fold. This increase is similar to exposures observed in poor metabolizers. Concurrent use of a strong CYP2D6 inhibitor with atomoxetine in poor metabolizers is not expected to increase atomoxetine exposure.
Atropine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Atropine; Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Contraindicated) According to the manufacturer of paroxetine, treatment initiation with paroxetine is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than paroxetine (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving paroxetine and requiring urgent treatment with IV methylene blue, paroxetine should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Paroxetine may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin; therefore, concurrent use of an MAO-A inhibitor with a serotonergic agent may result in a clinically significant interaction. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving SSRIs, serotonin/norepinephrine reuptake inhibitors, or clomipramine. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. One case describes a patient receiving citalopram who experienced agitation, restlessness, pupil dilation with sluggish response to light, myoclonic movements of the lower limbs, and brisk reflexes following an infusion of methylene blue, while another patient receiving paroxetine developed tachycardia, agitation, dystonia and abnormal eye movements. During a retrospective study of 193 surgical patients who had received a methylene blue injection, it was found that all 12 of the patients who experienced postoperative neurological sequelae had been taking a serotonin reuptake inhibitor preoperatively. One of the 12 patients experienced cardiopulmonary arrest and died. Of the remaining 181 patients who did not experience neurological sequelae, 8.8% were taking a serotonin reuptake inhibitor. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used. (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin.
Atropine; Difenoxin: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Atropine; Edrophonium: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Barbiturates: (Moderate) Barbiturates may induce various hepatic CYP450 isoenzymes, including those responsible for the metabolism of paroxetine. Clinicians should be aware of the potential for reduced SSRI efficacy with concurrent administration of a barbiturate, especially in chronic use.
Belladonna Alkaloids; Ergotamine; Phenobarbital: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used. (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Belladonna; Opium: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Benzhydrocodone; Acetaminophen: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of benzhydrocodone and paroxetine because of the potential risk of serotonin syndrome. Discontinue benzhydrocodone if serotonin syndrome is suspected. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Contraindicated) According to the manufacturer of paroxetine, treatment initiation with paroxetine is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than paroxetine (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving paroxetine and requiring urgent treatment with IV methylene blue, paroxetine should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Paroxetine may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin; therefore, concurrent use of an MAO-A inhibitor with a serotonergic agent may result in a clinically significant interaction. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving SSRIs, serotonin/norepinephrine reuptake inhibitors, or clomipramine. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. One case describes a patient receiving citalopram who experienced agitation, restlessness, pupil dilation with sluggish response to light, myoclonic movements of the lower limbs, and brisk reflexes following an infusion of methylene blue, while another patient receiving paroxetine developed tachycardia, agitation, dystonia and abnormal eye movements. During a retrospective study of 193 surgical patients who had received a methylene blue injection, it was found that all 12 of the patients who experienced postoperative neurological sequelae had been taking a serotonin reuptake inhibitor preoperatively. One of the 12 patients experienced cardiopulmonary arrest and died. Of the remaining 181 patients who did not experience neurological sequelae, 8.8% were taking a serotonin reuptake inhibitor. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used. (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin.
Benztropine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Betrixaban: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like betrixaban. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Bismuth Subsalicylate: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin.
Bismuth Subsalicylate; Metronidazole; Tetracycline: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin.
Brexpiprazole: (Major) Because brexpiprazole is primarily metabolized by CYP3A4 and CYP2D6, the manufacturer recommends that the brexpiprazole dose be reduced to one-half of the usual dose in patients receiving a strong CYP2D6 inhibitor and one-quarter (25%) of the usual dose in patients receiving a moderate to strong inhibitor of CYP3A4 in combination with a moderate to strong inhibitor of CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. If these agents are used in combination, the patient should be carefully monitored for brexpiprazole-related adverse reactions. It should be noted that no dosage adjustment is needed in patients taking a strong CYP2D6 inhibitor who are receiving brexpiprazole as adjunct treatment for major depressive disorder because CYP2D6 considerations are already factored into general dosing recommendations.
Brimonidine; Timolol: (Moderate) Timolol is significantly metabolized by CYP2D6 isoenzymes. CYP2D6 inhibitors, such as paroxetine, could theoretically impair timolol metabolism; the clinical significance of such interactions is unknown.
Brompheniramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Carbetapentane; Phenylephrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Dextromethorphan; Guaifenesin: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Guaifenesin; Hydrocodone: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Hydrocodone; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Phenylephrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Pseudoephedrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as brompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Budesonide; Glycopyrrolate; Formoterol: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Buprenorphine: (Moderate) If concomitant use of buprenorphine and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Buprenorphine; Naloxone: (Moderate) If concomitant use of buprenorphine and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Bupropion: (Moderate) Bupropion and hydroxybupropion, the major active metabolite, are inhibitors of CYP2D6 in vitro. Coadministration of bupropion with medications that are metabolized by CYP2D6 should be approached with caution. Many selective serotonin reuptake inhibitors (SSRIs) are CYP2D6 substrates including paroxetine. Although clinical evidence of interactions is lacking, plasma concentrations of SSRIs metabolized by CYP2D6 may be increased if bupropion is added. In addition, in vitro studies suggest that paroxetine inhibit the hydroxylation of bupropion.
Bupropion; Naltrexone: (Moderate) Bupropion and hydroxybupropion, the major active metabolite, are inhibitors of CYP2D6 in vitro. Coadministration of bupropion with medications that are metabolized by CYP2D6 should be approached with caution. Many selective serotonin reuptake inhibitors (SSRIs) are CYP2D6 substrates including paroxetine. Although clinical evidence of interactions is lacking, plasma concentrations of SSRIs metabolized by CYP2D6 may be increased if bupropion is added. In addition, in vitro studies suggest that paroxetine inhibit the hydroxylation of bupropion.
Buspirone: (Moderate) Coadministration of buspirone and paroxetine may increase the risk of serotonin syndrome. Serotonin syndrome has been reported with both drugs when taken alone, but especially when coadministered with other serotonergic agents. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome. Discontinue serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Butalbital; Acetaminophen; Caffeine; Codeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Cangrelor: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication (e.g., gastrointestinal bleeding, ecchymosis, epistaxis, hematomas, petechiae, hemorrhage) in patients receiving platelet inhibitors (e.g., cangrelor). Patients should be instructed to monitor for signs and symptoms of bleeding while taking an SSRI concurrently with an antiplatelet medication and to promptly report any bleeding events to the practitioner.
Capsaicin; Metaxalone: (Moderate) Concomitant use of selective serotonin reuptake inhibitors (SSRIs) and metaxalone may increase the risk for serotonin syndrome. Monitor patients for serotonin syndrome if concomitant use is necessary.
Carbetapentane; Chlorpheniramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbetapentane; Chlorpheniramine; Phenylephrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbetapentane; Diphenhydramine; Phenylephrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbetapentane; Phenylephrine; Pyrilamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as pyrilamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbetapentane; Pyrilamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as pyrilamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbinoxamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as carbinoxamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbinoxamine; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as carbinoxamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbinoxamine; Hydrocodone; Phenylephrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as carbinoxamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbinoxamine; Hydrocodone; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as carbinoxamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbinoxamine; Phenylephrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as carbinoxamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carbinoxamine; Pseudoephedrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as carbinoxamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Carvedilol: (Minor) Inhibitors of the hepatic CYP450 isozyme CYP 2D6, such as paroxetine, may inhibit the hepatic oxidative metabolism of carvedilol.
Celecoxib; Tramadol: (Moderate) Monitor for reduced efficacy of tramadol, signs of opioid withdrawal, seizures, or serotonin syndrome if coadministration with paroxetine is necessary. If paroxetine is discontinued, consider a dose reduction of tramadol and frequently monitor for signs of respiratory depression and sedation. Tramadol is a CYP2D6 substrate and paroxetine is a CYP2D6 inhibitor. Concomitant use of tramadol with CYP2D6 inhibitors can increase the plasma concentration of tramadol and decrease the plasma concentration of the active metabolite M1. Since M1 is a more potent mu-opioid agonist, decreased M1 exposure could result in decreased therapeutic effects, and may result in signs and symptoms of opioid withdrawal in patients who have developed physical dependence to tramadol. Increased tramadol exposure can result in increased or prolonged therapeutic effects and increased risk for serious adverse events including seizures and serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Cevimeline: (Moderate) Monitor for an increase in cevimeline-related adverse effects if concomitant use of paroxetine is necessary. Concomitant use may increase cevimeline exposure. Cevimeline is a CYP2D6 substrate; paroxetine is a strong CYP2D6 inhibitor.
Chlophedianol; Dexbrompheniramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as dexbrompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as dexchlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlordiazepoxide; Amitriptyline: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of amitriptyline, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and amitriptyline may exhibit significant anticholinergic effects that may be additive during concurrent use.
Chlordiazepoxide; Clidinium: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Chlorpheniramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Codeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of dihydrocodeine and paroxetine because of the potential risk of serotonin syndrome, reduced dihydrocodeine efficacy, and potential for opioid withdrawal symptoms. Discontinue dihydrocodeine if serotonin syndrome is suspected. It is recommended to avoid this combination when dihydrocodeine is being used for cough. Concomitant use may increase dihydrocodeine plasma concentrations, but decrease the plasma concentration of the active metabolite, dihydromorphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of dihydrocodeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease dihydrocodeine plasma concentrations and increase dihydromorphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Dihydrocodeine is primarily metabolized by CYP2D6 to dihydromorphine, and by CYP3A4. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Dihydrocodeine; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of dihydrocodeine and paroxetine because of the potential risk of serotonin syndrome, reduced dihydrocodeine efficacy, and potential for opioid withdrawal symptoms. Discontinue dihydrocodeine if serotonin syndrome is suspected. It is recommended to avoid this combination when dihydrocodeine is being used for cough. Concomitant use may increase dihydrocodeine plasma concentrations, but decrease the plasma concentration of the active metabolite, dihydromorphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of dihydrocodeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease dihydrocodeine plasma concentrations and increase dihydromorphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Dihydrocodeine is primarily metabolized by CYP2D6 to dihydromorphine, and by CYP3A4. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Hydrocodone: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Hydrocodone; Phenylephrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Hydrocodone; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Phenylephrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpheniramine; Pseudoephedrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as chlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Chlorpromazine: (Major) Substantial increases in concentrations of phenothiazines such as chlorpromazine may occur due to CYP2D6 inhibition by paroxetine, which may increase the risk of adverse effects, including extrapyramidal symptoms. In addition, because chlorpromazine has been associated with QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. Lastly, both paroxetine and chlorpromazine may exhibit significant anticholinergic effects that may be additive during concurrent use.
Choline Salicylate; Magnesium Salicylate: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. A cohort study in > 26,000 patients found that SSRI use alone increased the risk for serious GI bleed by 3.6-fold; when an SSRI was combined with aspirin the risk was increased by > 5-fold. The absolute risk of GI bleed from concomitant therapy with aspirin and a SSRI was low (20/2640 patients) in this cohort study and the clinician may determine that the combined use of these drugs is appropriate.
Cilostazol: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving platelet inhibitors. Monitor for signs and symptoms of bleeding.
Cimetidine: (Moderate) Cimetidine inhibits cytochrome isoenzymes CYP1A2, CYP2C9, and CYP3A4 while paroxetine is metabolized by isoenzyme CYP2D6. Although one would assume no interaction would occur, several studies have shown that cimetidine can increase paroxetine AUC. While significant adverse effects have not been reported, patients should be monitored carefully for an increased response to paroxetine if cimetidine is coadministered. Dosage adjustments of paroxetine should be based on clinical effect for the individual.
Cinacalcet: (Minor) Cinacalcet, a strong in vitro inhibitor of the CYP2D6 cytochrome P450 enzyme, may theoretically increase serum concentrations of other drugs metabolized by this enzyme, including paroxetine.
Citalopram: (Major) Due to the similarity in pharmacology of paroxetine and citalopram and the potential for serious adverse reactions, including serotonin syndrome, these selective serotonin reuptake inhibitors (SSRIs) should not be administered together. It is advisable to monitor for signs and symptoms of serotonin syndrome during an overlapping transition from one SSRI to another SSRI.
Class IC Antiarrhythmics: (Major) Paroxetine impairs metabolism of the cytochrome P-450 isoenzyme CYP2D6 pathway at therapeutic doses. Although no clinical data are available, paroxetine should be used cautiously in patients receiving type IC antiarrhythmics and mexiletine since these antiarrhythmics are metabolized by this isozyme. Inhibition of CYP2D6 can result in increased concentrations of Class IC antiarrhythmics which may increase the risk of side effects or proarrhythmia.
Clemastine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as clemastine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Clomipramine: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of clomipramine, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and clomipramine may exhibit significant anticholinergic effects that may be additive during concurrent use.
Clopidogrel: (Moderate) Carefully monitor patients for signs and symptoms of bleeding during coadministration of paroxetine and clopidogrel. Selective serotonin reuptake inhibitors (SSRIs) affect platelet activation; therefore, concomitant use may increase the risk of bleeding.
Clozapine: (Moderate) Paroxetine is a potent inhibitor of CYP2D6, which may result in decreased clearance of CYP2D6 substrates such as clozapine. Minor to modest (less than 2-fold) elevations in concentrations of clozapine and its metabolites have been reported during concurrent use of paroxetine. Clozapine is associated with a risk for QT prolongation and torsade de pointe (TdP). Elevated plasma concentrations of clozapine occurring through CYP2D6 inhibition may increase the risk of life-threatening arrhythmias. sedation, anticholinergic effects, seizures, orthostasis, or other adverse effects. According to the manufacturer, patients receiving clozapine in combination with an inhibitor of CYP2D6 should be monitored for adverse reactions. Consideration should be given to reducing the clozapine dose if necessary. If the inhibitor is discontinued after dose adjustments are made, monitor for lack of clozapine effectiveness and consider increasing the clozapine dose if necessary. Lastly, both paroxetine and clozapine may exhibit significant anticholinergic effects which may be additive during concurrent therapy.
Cobicistat: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of selective serotonin reuptake inhibitors (SSRIs) and cobicistat. Concurrent use may result in elevated SSRI plasma concentrations. Predictions regarding this interaction can be made based on the metabolic pathways of these drugs. All SSRIs are substrates for the hepatic isoenzyme CYP2D6, while citalopram, escitalopram, and sertraline are also substrates for CYP3A4; cobicistat is an inhibitor of both CYP2D6 and CYP3A4.
Cocaine: (Major) Concomitant use of cocaine with drugs that have CNS serotonergic properties, such as SSRIs, could potentiate serotonin neurotransmission, and result in the serotonin syndrome. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. Patients receiving this combination should be monitored for the emergence of serotonin syndrome or neuroleptic malignant syndrome-like reactions. Additionally, citalopram causes dose-dependent QT interval prolongation. Local anesthetics (e.g., cocaine) are associated with a possible risk for QT prolongation and according to the manufacturer of citalopram, concurrent use of citalopram with other drugs that prolong the QT interval is not recommended. If concurrent therapy is considered essential, ECG monitoring is recommended.
Codeine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Codeine; Guaifenesin: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Codeine; Guaifenesin; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Codeine; Phenylephrine; Promethazine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Promethazine is a substrate for CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because promethazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. In addition, both paroxetine and promethazine exhibit anticholinergic effects that may be additive during combined therapy. The risk of other adverse effects of promethazine may also be increased, including sedation and extrapyramidal symptoms.
Codeine; Promethazine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Promethazine is a substrate for CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because promethazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. In addition, both paroxetine and promethazine exhibit anticholinergic effects that may be additive during combined therapy. The risk of other adverse effects of promethazine may also be increased, including sedation and extrapyramidal symptoms.
Cyclobenzaprine: (Moderate) Cyclobenzaprine and paroxetine both exhibit anticholinergic activity, and anticholinergic side effects can be additive. Monitor for anticholinergic-related effects such as constipation and urinary retention. Additive CNS effects causing sedation and/or dizziness is also possible. Dosage adjustments of either or both drugs may be necessary. There is the possibility of serotonin syndrome with this combination. If these drugs must be used together, closely monitor the patient for signs and symptoms of serotonin syndrome. If such a reaction develops, immediately discontinue all serotonergic medications and implement appropriate medical treatment.
Cyproheptadine: (Moderate) Cyproheptadine is a serotonin antagonist in the CNS and can oppose the pharmacologic actions of selective serotonin reuptake inhibitors (SSRIs) such as paroxetine. Cyproheptadine has been used for the management of orgasm dysfunction caused by the SSRIs and for the adjunctive treatment of SSRI overdose (i.e., serotonin syndrome) in emergency situations; however, a reversal of antidepressant effects may occur when cyproheptadine is given in a routine manner along with the SSRIs due to the serotonin antagonistic effects of cyproheptadine. In addition, additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as cyproheptadine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Dabigatran: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like dabigatran. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Dacomitinib: (Moderate) Monitor for increased toxicity of paroxetine if coadministered with dacomitinib. Coadministration may increase serum concentrations of paroxetine. Paroxetine is a CYP2D6 substrate; dacomitinib is a strong CYP2D6 inhibitor.
Dalteparin: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like low molecular weight heparins. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Danaparoid: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like danaparoid. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Darifenacin: (Moderate) Paroxetine inhibits CYP2D6. Serum concentrations of darifenacin, a CYP2D6 substrate, may increase when used in combination with paroxetine. Patients should be monitored for increased anticholinergic effects if these drugs are coadministered.
Darunavir: (Moderate) Use caution when coadministering darunavir with paroxetine, as decreased SSRI concentrations may be seen. If paroxetine is coadministered with darunavir, carefully titrate the dose of paroxetine based on a clinical assessment of antidepressant response.
Darunavir; Cobicistat: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of selective serotonin reuptake inhibitors (SSRIs) and cobicistat. Concurrent use may result in elevated SSRI plasma concentrations. Predictions regarding this interaction can be made based on the metabolic pathways of these drugs. All SSRIs are substrates for the hepatic isoenzyme CYP2D6, while citalopram, escitalopram, and sertraline are also substrates for CYP3A4; cobicistat is an inhibitor of both CYP2D6 and CYP3A4. (Moderate) Use caution when coadministering darunavir with paroxetine, as decreased SSRI concentrations may be seen. If paroxetine is coadministered with darunavir, carefully titrate the dose of paroxetine based on a clinical assessment of antidepressant response.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of selective serotonin reuptake inhibitors (SSRIs) and cobicistat. Concurrent use may result in elevated SSRI plasma concentrations. Predictions regarding this interaction can be made based on the metabolic pathways of these drugs. All SSRIs are substrates for the hepatic isoenzyme CYP2D6, while citalopram, escitalopram, and sertraline are also substrates for CYP3A4; cobicistat is an inhibitor of both CYP2D6 and CYP3A4. (Moderate) Use caution when coadministering darunavir with paroxetine, as decreased SSRI concentrations may be seen. If paroxetine is coadministered with darunavir, carefully titrate the dose of paroxetine based on a clinical assessment of antidepressant response.
Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Major) A dose reduction of paroxetine may be necessary during co-administration of ritonavir. Concurrent use of CYP2D6 substrates, such as paroxetine, with ritonavir could result in increases (up to 2-fold) in the AUC of paroxetine. Paroxetine is metabolized by the hepatic isoenzyme CYP2D6; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Delavirdine: (Moderate) Delavirdine is a potent inhibitors of cytochrome P450 2D6, and may theoretically decrease paroxetine metabolism leading to increased adverse reactions.
Desipramine: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of desipramine, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and desipramine may exhibit significant anticholinergic effects that may be additive during concurrent use.
Desmopressin: (Minor) Additive hyponatremic effects may be seen in patients treated with desmopressin and drugs associated with water intoxication, hyponatremia, or SIADH including SSRIs. Use combination with caution, and monitor patients for signs and symptoms of hyponatremia, which may include monitoring serum sodium or electrolytes periodically. Ensure the patient is compliant with fluid restrictions and intake.
Desvenlafaxine: (Major) Due to similarity of pharmacology and the potential for additive adverse effects, including serotonin syndrome, selective serotonin reuptake inhibitors (SSRIs) should generally not be administered with serotonin norepinephrine reuptake inhibitors like desvenlafaxine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Discontinuation symptoms have been reported when switching from other antidepressants to desvenlafaxine. It may be advisable to taper the previous antidepressant to minimize discontinuation symptoms. If serotonin syndrome is suspected, desvenlafaxine and concurrent serotonergic agents should be discontinued. Dosage adjustments of fluoxetine or paroxetine may be necessary during concurrent use of desvenlafaxine. Although clinical studies have shown that desvenlafaxine does not have a clinically relevant effect on CYP2D6 inhibition at doses of 100 mg/day, the manufacturer recommends that primary substrates of CYP2D6 be dosed at the original level when co-administered with desvenlafaxine 100 mg or lower or when desvenlafaxine is discontinued. The dose of these CYP2D6 substrates should be reduced by up to one-half if co-administered with desvenlafaxine 400 mg/day.
Deutetrabenazine: (Major) Do not exceed 18 mg/dose or 36 mg/day of deutetrabenazine if must use concurrently with a strong CYP2D6 inhibitor. Paroxetine is a strong CYP2D6 inhibitor, and the metabolites of deutetrabenazine, alpha- and beta-HTBZ, are CYP2D6 substrates. The systemic exposure of alpha- and beta-HTBZ may be increased resulting in an increase in deutetrabenazine-related adverse reactions, like QT prolongation and drowsiness. After 8 days of paroxetine 20 mg PO daily, systemic exposure (AUC) of alpha- and beta-HTBZ increased 1.9-fold and 6.5-fold, respectively, following a single 22.5 mg dose of deutetrabenazine. The clearance of alpha- and beta-HTBZ was reduced, with corresponding increases in mean half-life of 1.5-fold and 2.7-fold, respectively. The Cmax of alpha- and beta-HTBZ increased 1.2-fold and 2.2-fold, respectively.
Dexbrompheniramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as dexbrompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Dexbrompheniramine; Pseudoephedrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as dexbrompheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Dexchlorpheniramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as dexchlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as dexchlorpheniramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Dextromethorphan; Guaifenesin: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Dextromethorphan; Guaifenesin; Potassium Guaiacolsulfonate: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome.
Dextromethorphan; Quinidine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Quinidine inhibits CYP2D6 and may theoretically increase concentrations of other drugs metabolized by this enzyme. Caution is recommended when administering quinidine with CYP2D6 substrates, including paroxetine.
Dicyclomine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Digoxin: (Minor) Paroxetine may slightly decrease mean digoxin area under the curve values. Until more clinical data are known, patients should be monitored for loss of digoxin clinical effect if paroxetine is added.
Dihydrocodeine; Guaifenesin; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of dihydrocodeine and paroxetine because of the potential risk of serotonin syndrome, reduced dihydrocodeine efficacy, and potential for opioid withdrawal symptoms. Discontinue dihydrocodeine if serotonin syndrome is suspected. It is recommended to avoid this combination when dihydrocodeine is being used for cough. Concomitant use may increase dihydrocodeine plasma concentrations, but decrease the plasma concentration of the active metabolite, dihydromorphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of dihydrocodeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease dihydrocodeine plasma concentrations and increase dihydromorphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Dihydrocodeine is primarily metabolized by CYP2D6 to dihydromorphine, and by CYP3A4. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Dihydroergotamine: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Dimenhydrinate: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as dimenhydrinate. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Diphenhydramine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Diphenhydramine; Hydrocodone; Phenylephrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Diphenhydramine; Ibuprofen: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Diphenhydramine; Naproxen: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Diphenhydramine; Phenylephrine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as diphenhydramine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Diphenoxylate; Atropine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Dipyridamole: (Moderate) Platelet aggregation may be impaired by SSRIs due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving platelet inhibitors. Monitor for signs and symptoms of bleeding.
Disopyramide: (Moderate) Additive anticholinergic effects may be seen when drugs with anticholinergic properties like disopyramide and paroxetine are used concomitantly. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation.
Diuretics: (Moderate) Patients receiving a diuretic during treatment with paroxetine may be at greater risk of developing syndrome of inappropriate antidiuretic hormone secretion (SIADH). Hyponatremia due to SIADH has been reported during therapy with SSRIs. Cases involving serum sodium levels lower than 110 mmol/l have occurred. Hyponatremia may be potentiated by agents which can cause sodium depletion such as diuretics. Discontinuation of paroxetine should be considered in patients who develop symptomatic hyponatremia.
Dolasetron: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering dolasetron with other drugs that have serotonergic properties such as paroxetine. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome is suspected, discontinue dolasetron and concurrent serotonergic agents and initiate appropriate medical treatment. In addition, because dolasetron is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Donepezil: (Moderate) Clinical monitoring for drug efficacy, GI or cholinergic effects (e.g., bradycardia or irregular heartbeat), or unusual changes in mood or behavior is recommended during coadministration of donepezil and paroxetine. The plasma concentrations of donepezil may be increased when administered concurrently with paroxetine. Paroxetine is a strong inhibitor of CYP2D6 inhibitor and donepezil undergoes some metabolism by CYP2D6. Paroxetine exhibits anticholinergic effects that may be problematic in the dementia population.
Donepezil; Memantine: (Moderate) Clinical monitoring for drug efficacy, GI or cholinergic effects (e.g., bradycardia or irregular heartbeat), or unusual changes in mood or behavior is recommended during coadministration of donepezil and paroxetine. The plasma concentrations of donepezil may be increased when administered concurrently with paroxetine. Paroxetine is a strong inhibitor of CYP2D6 inhibitor and donepezil undergoes some metabolism by CYP2D6. Paroxetine exhibits anticholinergic effects that may be problematic in the dementia population.
Dorzolamide; Timolol: (Moderate) Timolol is significantly metabolized by CYP2D6 isoenzymes. CYP2D6 inhibitors, such as paroxetine, could theoretically impair timolol metabolism; the clinical significance of such interactions is unknown.
Doxepin: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of doxepin, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and doxepin may exhibit significant anticholinergic effects that may be additive during concurrent use.
Doxercalciferol: (Moderate) Doxercalciferol is converted in the liver to 1,25-dihydroxyergocalciferol, the major active metabolite, and 1-alpha, 24-dihydroxyvitamin D2, a minor metabolite. Although not specifically studied, cytochrome P450 enzyme inhibitors, including selective serotonin reuptake inhibitors (SSRIs), may inhibit the 25-hydroxylation of doxercalciferol, thereby decreasing the formation of the active metabolite and thus, decreasing efficacy. Patients should be monitored for a decrease in efficacy if SSRIs are coadministered with doxercalciferol.
Doxorubicin Liposomal: (Major) Avoid coadministration of paroxetine with doxorubicin due to increased systemic exposure of doxorubicin resulting in increased treatment-related adverse reactions. Paroxetine is a strong CYP2D6 inhibitor and doxorubicin is a major substrate of CYP3D6. Concurrent use of CYP2D6 inhibitors with doxorubicin has resulted in clinically significant interaction
Doxorubicin: (Major) Avoid coadministration of paroxetine with doxorubicin due to increased systemic exposure of doxorubicin resulting in increased treatment-related adverse reactions. Paroxetine is a strong CYP2D6 inhibitor and doxorubicin is a major substrate of CYP3D6. Concurrent use of CYP2D6 inhibitors with doxorubicin has resulted in clinically significant interaction
Doxylamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as doxylamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Doxylamine; Pyridoxine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as doxylamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Duloxetine: (Major) Due to similarity of pharmacology and the potential for additive adverse effects, including serotonin syndrome, selective serotonin reuptake inhibitors (SSRIs) such as paroxetine should generally not be administered with serotonin norepinephrine reuptake inhibitors (SNRIs) such as duloxetine.
Dutasteride; Tamsulosin: (Moderate) Use caution when administering tamsulosin with a strong CYP2D6 inhibitor such as paroxetine. Tamsulosin is extensively metabolized by CYP2D6 hepatic enzymes. In clinical evaluation, concomitant treatment with paroxetine resulted in an increase in the Cmax and AUC of tamsulosin by a factor of 1.3 and 1.6, respectively. If concomitant use in necessary, monitor patient closely for increased side effects.
Edoxaban: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like edoxaban. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Eletriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering eletriptan with paroxetine. Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists and selective serotonin reuptake inhibitors (SSRIs). Some patients had used the combination previously without incident when serotonin syndrome occurred. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly after a dose increase of the SSRI or the addition of other serotonergic medications to an existing SSRI regimen. Discontinue paroxetine and eletriptan and initiate symptomatic treatment if serotonin syndrome occurs.
Eliglustat: (Major) In extensive or intermediate CYP2D6 metabolizers (EMs or IMs), coadministration of paroxetine and eliglustat requires dosage reduction of eliglustat to 84 mg PO once daily; however, coadministration of eliglustat with both paroxetine and a strong or moderate CYP3A inhibitor is contraindicated. Paroxetine is a substrate and strong inhibitor of CYP2D6; eliglustat is a CYP2D6 and CYP3A substrate and a CYP2D6 inhibitor. Coadministration of eliglustat with CYP2D6 inhibitors, such as paroxetine, may increase eliglustat exposure and the risk of serious adverse events (e.g., QT prolongation and cardiac arrhythmias). In addition, coadministration of eliglustat with CYP2D6 substrates (e.g., paroxetine) may result in increased concentrations of the concomitant drug; monitor patients closely and consider reducing the dosage of paroxetine and titrating to clinical effect. During clinical trials in EMs (n = 30), Cmax and AUC of eliglustat increased 7-fold and 8.4-fold, respectively, after co-administration of eliglustat 84 mg PO twice daily with paroxetine 30 mg. Physiology-based pharmacokinetic (PBPK) models suggest that paroxetine may increase the Cmax and AUC of eliglustat 2.1- and 2.3-fold, respectively, in IMs. In addition, PBPK modeling suggests concomitant use of eliglustat (84 mg PO twice daily) with paroxetine (strong 2D6 inhibitor) and ketoconazole (strong 3A4 inhibitor) may increase the Cmax and AUC of eliglustat 16.7- and 24.2-fold, respectively, in EMs and 7.5- and 9.8-fold, respectively, in IMs.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of selective serotonin reuptake inhibitors (SSRIs) and cobicistat. Concurrent use may result in elevated SSRI plasma concentrations. Predictions regarding this interaction can be made based on the metabolic pathways of these drugs. All SSRIs are substrates for the hepatic isoenzyme CYP2D6, while citalopram, escitalopram, and sertraline are also substrates for CYP3A4; cobicistat is an inhibitor of both CYP2D6 and CYP3A4.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of selective serotonin reuptake inhibitors (SSRIs) and cobicistat. Concurrent use may result in elevated SSRI plasma concentrations. Predictions regarding this interaction can be made based on the metabolic pathways of these drugs. All SSRIs are substrates for the hepatic isoenzyme CYP2D6, while citalopram, escitalopram, and sertraline are also substrates for CYP3A4; cobicistat is an inhibitor of both CYP2D6 and CYP3A4.
Encainide: (Major) Paroxetine impairs metabolism of the cytochrome P-450 isoenzyme CYP2D6 pathway at therapeutic doses. Although no clinical data are available, paroxetine should be used cautiously in patients receiving type IC antiarrhythmics and mexiletine since these antiarrhythmics are metabolized by this isozyme. Inhibition of CYP2D6 can result in increased concentrations of Class IC antiarrhythmics which may increase the risk of side effects or proarrhythmia.
Enoxaparin: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like low molecular weight heparins. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Eptifibatide: (Moderate) Platelet aggregation may be impaired by SSRIs due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving platelet inhibitors. Monitor for signs and symptoms of bleeding.
Ergoloid Mesylates: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Ergonovine: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Ergot alkaloids: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Ergotamine: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Ergotamine; Caffeine: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Escitalopram: (Major) Due to the similarity in pharmacology of paroxetine and escitalopram and the potential for serious adverse reactions, including serotonin syndrome, these selective serotonin reuptake inhibitors (SSRIs) should not be administered together. It is advisable to monitor for signs and symptoms of serotonin syndrome during an overlapping transition from one SSRI to another SSRI.
Fenfluramine: (Moderate) Use fenfluramine and selective serotonin reuptake inhibitors with caution due to an increased risk of serotonin syndrome. Monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Fentanyl: (Moderate) If concomitant use of fentanyl and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Flavoxate: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Flecainide: (Major) Paroxetine impairs metabolism of the cytochrome P-450 isoenzyme CYP2D6 pathway at therapeutic doses. Although no clinical data are available, paroxetine should be used cautiously in patients receiving type IC antiarrhythmics and mexiletine since these antiarrhythmics are metabolized by this isozyme. Inhibition of CYP2D6 can result in increased concentrations of Class IC antiarrhythmics which may increase the risk of side effects or proarrhythmia.
Fluoxetine: (Major) Due to the similarity in pharmacology of fluoxetine and paroxetine and the potential for serious adverse reactions, including serotonin syndrome, these selective serotonin reuptake inhibitors (SSRIs) should not be administered together. It is advisable to monitor for signs and symptoms of serotonin syndrome during an overlapping transition from one SSRI to another SSRI. In addition, because fluoxetine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes (TdP), concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Fluphenazine: (Moderate) Substantial increases in concentrations of phenothiazines, such as fluphenazine, may occur due to CYP2D6 inhibition by paroxetine, which may increase the risk of adverse effects, such as extrapyramidal symptoms. In addition, because fluphenazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. Additive anticholinergic effects are also possible.
Fluvoxamine: (Major) Due to the similarity in pharmacology of paroxetine and fluvoxamine and the potential for serious adverse reactions, including serotonin syndrome, these selective serotonin reuptake inhibitors (SSRIs) should not be administered together. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. It is advisable to monitor for signs and symptoms of serotonin syndrome during an overlapping transition from one SSRI to another SSRI.
Fondaparinux: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like fondaparinux. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Fosamprenavir: (Moderate) The combined use of fosamprenavir, boosted with ritonavir, and paroxetine significantly reduced plasma concentrations of paroxetine. Adjust paroxetine dosage based upon tolerability and efficacy of the combined regimen.
Fosphenytoin: (Moderate) Paroxetine may interact with either phenytoin (or fosphenytoin), although studies have not addressed if clinically important interactions occur when the two drugs are chronically dosed. Initial studies suggested no significant effect of paroxetine on phenytoin serum concentrations, however, clinicians should keep in mind that paroxetine itself is a potent inhibitor of CYP2D6, and both phenytoin and paroxetine exhibit non-linear pharmacokinetics. One post-marketing case report of elevated phenytoin serum concentrations occurring in a patient after 4 weeks of concomitant therapy with paroxetine and phenytoin has been reported to the manufacturer. In addition, phenytoin, via hepatic enzyme induction, may reduce paroxetine AUC by 50% and half-life by 35%. No initial dosage adjustment is recommended, but subsequent dosage adjustments of paroxetine or phenytoin should be based on clinical effect. Monitoring of phenytoin concentrations during concomitant therapy is recommended.
Frovatriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering frovatriptan with selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists and SSRIs. Some patients had used the combination previously without incident when serotonin syndrome occurred. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly after a dose increase of the SSRI or the addition of other serotonergic medications to an existing SSRI regimen. Discontinue the SSRI and frovatriptan and initiate symptomatic treatment if serotonin syndrome occurs.
Gefitinib: (Moderate) Monitor for an increase in gefitinib-related adverse reactions if coadministration with paroxetine is necessary; the risk is increased in CYP2D6 poor metabolizers. Based on in vitro data, gefitinib is metabolized to O-desmethyl gefitinib by CYP2D6 and paroxetine is a strong CYP2D6 inhibitor. In healthy CYP2D6 poor metabolizers, the concentration of O-desmethyl gefitinib was not measurable and mean exposure to gefitinib was 2-fold higher compared to extensive metabolizers. The impact of CYP2D6 inhibitors on gefitinib pharmacokinetics has not been evaluated; however, the manufacturer recommends precautions based on exposure in patients with poor CYP2D6 metabolism.
Gilteritinib: (Major) Avoid coadministration of paroxetine with gilteritinib if possible due to the potential for decreased response to paroxetine. Gilteritinib inhibits human 5HT2B receptor or sigma nonspecific receptors, which may reduce the effects of drugs like paroxetine that target these receptors.
Glycopyrrolate: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Glycopyrrolate; Formoterol: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Granisetron: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering granisetron with other drugs that have serotonergic properties such as paroxetine. If serotonin syndrome is suspected, discontinue granisetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death.
Guaifenesin; Hydrocodone: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Haloperidol: (Major) Haloperidol is metabolized by CYP2D6 and CYP3A4 and concurrent use with inhibitors of these isoenzymes may result in elevated haloperidol plasma concentrations and adverse effects including extrapyramidal symptoms or QT prolongation. Paroxetine is a potent CYP2D6 inhibitor. Because symptoms consistent with elevated haloperidol levels have been observed during co-administration of SSRIs and haloperidol, patients receiving these combinations should be monitored for adverse effects such as dizziness, sedation, impaired psychomotor performance, extrapyramidal symptoms, and adverse cardiac effects.
Heparin: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like heparin. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Homatropine; Hydrocodone: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Hydrocodone: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Hydrocodone; Ibuprofen: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Hydrocodone; Phenylephrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Hydrocodone; Potassium Guaiacolsulfonate: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Hydrocodone; Potassium Guaiacolsulfonate; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Hydrocodone; Pseudoephedrine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of hydrocodone and paroxetine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue hydrocodone if serotonin syndrome is suspected. It is recommended to avoid this combination when hydrocodone is being used for cough. Concomitant use of hydrocodone with paroxetine may increase hydrocodone plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of hydrocodone until stable drug effects are achieved. Discontinuation of paroxetine could decrease hydrocodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to hydrocodone. If paroxetine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Hydrocodone is a substrate for CYP2D6. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Hydromorphone: (Moderate) If concomitant use of hydromorphone and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Hydroxyzine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as hydroxyzine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Hyoscyamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Contraindicated) According to the manufacturer of paroxetine, treatment initiation with paroxetine is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than paroxetine (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving paroxetine and requiring urgent treatment with IV methylene blue, paroxetine should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Paroxetine may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin; therefore, concurrent use of an MAO-A inhibitor with a serotonergic agent may result in a clinically significant interaction. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving SSRIs, serotonin/norepinephrine reuptake inhibitors, or clomipramine. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. One case describes a patient receiving citalopram who experienced agitation, restlessness, pupil dilation with sluggish response to light, myoclonic movements of the lower limbs, and brisk reflexes following an infusion of methylene blue, while another patient receiving paroxetine developed tachycardia, agitation, dystonia and abnormal eye movements. During a retrospective study of 193 surgical patients who had received a methylene blue injection, it was found that all 12 of the patients who experienced postoperative neurological sequelae had been taking a serotonin reuptake inhibitor preoperatively. One of the 12 patients experienced cardiopulmonary arrest and died. Of the remaining 181 patients who did not experience neurological sequelae, 8.8% were taking a serotonin reuptake inhibitor. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used. (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin.
Ibuprofen; Oxycodone: (Moderate) If concomitant use of oxycodone and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Iloperidone: (Major) Reduce the iloperidone dose by one-half if coadministered with paroxetine. If paroxetine is discontinued, increase the iloperidone dose to the previous level. Increased iloperidone exposure may occur with concurrent use. Iloperidone is a CYP2D6 substrate. Paroxetine is a strong inhibitor of CYP2D6. Coadministration of paroxetine increased mean steady-state peak concentrations of iloperidone and its metabolite P88, by about 1.6 fold, and decreased mean steady-state peak concentrations of its metabolite P95 by one-half.
Imatinib: (Moderate) Imatinib is a potent inhibitor of cytochrome P450 2D6, and may theoretically decrease paroxetine metabolism leading to increased adverse reactions.
Imipramine: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of imipramine, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and imipramine may exhibit significant anticholinergic effects that may be additive during concurrent use.
Indacaterol; Glycopyrrolate: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Isocarboxazid: (Contraindicated) Due to the risk of serotonin syndrome, monoamine oxidase inhibitors (MAOIs) intended to treat psychiatric disorders are contraindicated for use with selective serotonin reuptake inhibitors (SSRIs). MAOIs should not be used within 5 weeks of discontinuing treatment with fluoxetine or within 14 days of discontinuing treatment with other SSRIs. Conversely, SSRIs should not be initiated within 14 days of stopping an MAOI. Monitor the patient for serotonin-related effects during therapy transitions.
Isoniazid, INH: (Major) Concurrent use of isoniazid and selective serotonin reuptake inhibitors (SSRIs) should be avoided if possible. Isoniazid is chemically related to iproniazid, a drug that was known to possess MAO inhibiting activity. Although isoniazid does not inhibit mitochondrial MAO, it does appear to inhibit plasma MAO. Isoniazid may possess enough MAO inhibiting activity to produce clinical symptoms consistent with serotonergic excess when combined with SSRIs. Concurrent use of SSRIs and MAOIs may lead to serious reactions including serotonin syndrome or neuroleptic malignant syndrome-like reactions. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If combination therpay is necessary, patients should be monitored for the emergence of serotonin syndrome or neuroleptic malignant syndrome-like reactions.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Major) Concurrent use of isoniazid and selective serotonin reuptake inhibitors (SSRIs) should be avoided if possible. Isoniazid is chemically related to iproniazid, a drug that was known to possess MAO inhibiting activity. Although isoniazid does not inhibit mitochondrial MAO, it does appear to inhibit plasma MAO. Isoniazid may possess enough MAO inhibiting activity to produce clinical symptoms consistent with serotonergic excess when combined with SSRIs. Concurrent use of SSRIs and MAOIs may lead to serious reactions including serotonin syndrome or neuroleptic malignant syndrome-like reactions. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If combination therpay is necessary, patients should be monitored for the emergence of serotonin syndrome or neuroleptic malignant syndrome-like reactions.
Isoniazid, INH; Rifampin: (Major) Concurrent use of isoniazid and selective serotonin reuptake inhibitors (SSRIs) should be avoided if possible. Isoniazid is chemically related to iproniazid, a drug that was known to possess MAO inhibiting activity. Although isoniazid does not inhibit mitochondrial MAO, it does appear to inhibit plasma MAO. Isoniazid may possess enough MAO inhibiting activity to produce clinical symptoms consistent with serotonergic excess when combined with SSRIs. Concurrent use of SSRIs and MAOIs may lead to serious reactions including serotonin syndrome or neuroleptic malignant syndrome-like reactions. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If combination therpay is necessary, patients should be monitored for the emergence of serotonin syndrome or neuroleptic malignant syndrome-like reactions.
Lasmiditan: (Moderate) Serotonin syndrome may occur during coadministration of lasmiditan and selective serotonin reuptake inhibitors. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly after a dose increase or the addition of other serotonergic medications to an existing regimen. Discontinue all serotonergic agents if serotonin syndrome occurs and implement appropriate medical management.
Levomilnacipran: (Major) Because of the potential risk and severity of serotonin syndrome, concurrent use of levomilnacipran with other drugs that have serotonergic properties, such as selective serotonin reuptake inhibitors (SSRIs), should generally be avoided. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome is suspected, levomilnacipran and concurrent serotonergic agents should be discontinued.
Levorphanol: (Moderate) If concomitant use of levorphanol and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Linezolid: (Contraindicated) According to the manufacturer of paroxetine, treatment initiation with paroxetine is contraindicated in patients currently receiving linezolid due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than paroxetine (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving paroxetine and requiring urgent treatment with linezolid, paroxetine should be discontinued immediately and linezolid therapy initiated only if acceptable alternatives are not available and the potential benefits of linezolid outweigh the risks. The patient should be monitored for serotonin syndrome for two weeks or until 24 hours after the last dose of linezolid, whichever comes first. Paroxetine may be re-initiated 24 hours after the last dose of linezolid. Linezolid is an antibiotic that is also a non-selective monoamine oxidase (MAO) inhibitor. Since monoamine oxidase type A deaminates serotonin, administration of a non-selective MAO inhibitor concurrently with paroxetine can lead to serious reactions including serotonin syndrome or neuroleptic malignant syndrome-like reactions. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. Serotonin syndrome has been reported in patients receiving either citalopram, escitalopram, fluoxetine, or paroxetine in combination with linezolid.
Lithium: (Moderate) Lithium is an effective augmenting agent to antidepressants in treatment-resistant depression; however, lithium has central serotonin-enhancing effects and may increase the risk of serotonin syndrome when combined with selective serotonin reuptake inhibitors (SSRIs) such as paroxetine. Inform patients of the possible increased risk and monitor for serotonin syndrome, particularly during treatment initiation and dosage increases. If serotonin syndrome occurs, serotonergic agents should be discontinued and symptomatic treatment should be initiated.
Lofexidine: (Moderate) Monitor for orthostatic hypotension and bradycardia during concurrent use of lofexidine and paroxetine. Coadministration may increase lofexidine exposure. Lofexidine is a CYP2D6 substrate; paroxetine is a strong CYP2D6 inhibitor. Coadministration with paroxetine increased the lofexidine AUC by 28%.
Loperamide: (Moderate) The plasma concentration of loperamide, a CYP2D6 substrate, may be increased when administered concurrently with paroxetine, a potent CYP2D6 inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
Loperamide; Simethicone: (Moderate) The plasma concentration of loperamide, a CYP2D6 substrate, may be increased when administered concurrently with paroxetine, a potent CYP2D6 inhibitor. If these drugs are used together, monitor for loperamide-associated adverse reactions, such as CNS effects and cardiac toxicities (i.e., syncope, ventricular tachycardia, QT prolongation, torsade de pointes, cardiac arrest).
Lopinavir; Ritonavir: (Major) A dose reduction of paroxetine may be necessary during co-administration of ritonavir. Concurrent use of CYP2D6 substrates, such as paroxetine, with ritonavir could result in increases (up to 2-fold) in the AUC of paroxetine. Paroxetine is metabolized by the hepatic isoenzyme CYP2D6; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Lorcaserin: (Major) Based on the mechanism of action of lorcaserin and the theoretical potential for serotonin syndrome, use with extreme caution in combination with other drugs that may affect the serotonergic neurotransmitter systems, including, selective serotonin reuptake inhibitors (SSRIs). Patients receiving this combination should be monitored for the emergence of serotonin syndrome or Neuroleptic Malignant Syndrome (NMS) like signs and symptoms.
Low Molecular Weight Heparins: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like low molecular weight heparins. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Loxapine: (Moderate) Additive anticholinergic effects may be seen when drugs with anticholinergic properties like paroxetine and loxapine are used concomitantly. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation.
Magnesium Salicylate: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. A cohort study in > 26,000 patients found that SSRI use alone increased the risk for serious GI bleed by 3.6-fold; when an SSRI was combined with aspirin the risk was increased by > 5-fold. The absolute risk of GI bleed from concomitant therapy with aspirin and a SSRI was low (20/2640 patients) in this cohort study and the clinician may determine that the combined use of these drugs is appropriate.
Maprotiline: (Major) Paroxetine is a potent inhibitor of CYP2D6, the primary isoenzyme responsible for the metabolism of maprotiline. In several cases, symptoms of toxicity, including seizures, have been reported when SSRIs and cyclic antidepressants have been used together. In addition, because maprotiline is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. Patients receiving maprotiline should be monitored closely for toxicity if paroxetine is added.
Meclizine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with other medications having anticholinergic properties such as meclizine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Mepenzolate: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Meperidine: (Moderate) If concomitant use of meperidine and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Meperidine; Promethazine: (Moderate) If concomitant use of meperidine and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. (Moderate) Promethazine is a substrate for CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because promethazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. In addition, both paroxetine and promethazine exhibit anticholinergic effects that may be additive during combined therapy. The risk of other adverse effects of promethazine may also be increased, including sedation and extrapyramidal symptoms.
Mesoridazine: (Contraindicated) The use of paroxetine with mesoridazine is essentially contraindicated. Paroxetine is a potent inhibitor of CYP2D6 and may result in increased serum mesoridazine concentrations, leading to a risk for QT prolongation and heart arrhythmia, or other phenothiazine-related side effects. Mesoridazine has a well-established risk for QT prolongation and torsade de pointes.
Metaxalone: (Moderate) Concomitant use of selective serotonin reuptake inhibitors (SSRIs) and metaxalone may increase the risk for serotonin syndrome. Monitor patients for serotonin syndrome if concomitant use is necessary.
Methadone: (Moderate) Monitor patients for respiratory depression and sedation at frequent intervals if concomitant administration of methadone and paroxetine is necessary; consider reducing the methadone dose until stable effects are achieved. Concomitant use of methadone and paroxetine may increase the plasma concentration of methadone, resulting in increased or prolonged opioid effects. If paroxetine is discontinued, consider increasing the methadone dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Methadone is a CYP2D6 substrate and paroxetine is a CYP2D6 inhibitor. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Contraindicated) According to the manufacturer of paroxetine, treatment initiation with paroxetine is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than paroxetine (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving paroxetine and requiring urgent treatment with IV methylene blue, paroxetine should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Paroxetine may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin; therefore, concurrent use of an MAO-A inhibitor with a serotonergic agent may result in a clinically significant interaction. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving SSRIs, serotonin/norepinephrine reuptake inhibitors, or clomipramine. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. One case describes a patient receiving citalopram who experienced agitation, restlessness, pupil dilation with sluggish response to light, myoclonic movements of the lower limbs, and brisk reflexes following an infusion of methylene blue, while another patient receiving paroxetine developed tachycardia, agitation, dystonia and abnormal eye movements. During a retrospective study of 193 surgical patients who had received a methylene blue injection, it was found that all 12 of the patients who experienced postoperative neurological sequelae had been taking a serotonin reuptake inhibitor preoperatively. One of the 12 patients experienced cardiopulmonary arrest and died. Of the remaining 181 patients who did not experience neurological sequelae, 8.8% were taking a serotonin reuptake inhibitor. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma. (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Methscopolamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Methylene Blue: (Contraindicated) According to the manufacturer of paroxetine, treatment initiation with paroxetine is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than paroxetine (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving paroxetine and requiring urgent treatment with IV methylene blue, paroxetine should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Paroxetine may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin; therefore, concurrent use of an MAO-A inhibitor with a serotonergic agent may result in a clinically significant interaction. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving SSRIs, serotonin/norepinephrine reuptake inhibitors, or clomipramine. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. One case describes a patient receiving citalopram who experienced agitation, restlessness, pupil dilation with sluggish response to light, myoclonic movements of the lower limbs, and brisk reflexes following an infusion of methylene blue, while another patient receiving paroxetine developed tachycardia, agitation, dystonia and abnormal eye movements. During a retrospective study of 193 surgical patients who had received a methylene blue injection, it was found that all 12 of the patients who experienced postoperative neurological sequelae had been taking a serotonin reuptake inhibitor preoperatively. One of the 12 patients experienced cardiopulmonary arrest and died. Of the remaining 181 patients who did not experience neurological sequelae, 8.8% were taking a serotonin reuptake inhibitor. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma.
Methylergonovine: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Methylphenidate Derivatives: (Moderate) Caution should be observed when coadministering methylphenidate derivatives and the selective serotonin reuptake inhibitors (SSRIs). There are postmarketing reports of serotonin syndrome during concurrent use of methylphenidate derivatives with other serotonergic medications. Human pharmacologic studies have shown that methylphenidate may inhibit the metabolism of some SSRIs and downward dose adjustment of the SSRI may be required in some patients. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome. If serotonin syndrome occurs, serotonergic agents should be discontinued and appropriate medical management should be implemented.
Methysergide: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Metoclopramide: (Major) When metoclopramide is used with a potent CYP2D6 inhibitor for the treatment of gastroesophageal reflux (GERD), dosage reductions of oral metoclopramide are required, with maximum oral dosage not to exceed 30 mg/day (e.g., 5 mg 4 times daily or 10 mg 3 times daily). There is a known increase in metoclopramide exposure and an increased risk for extrapyramidal adverse reactions. Metoclopramide is a substrate of CYP2D6 and paroxetine is a strong CYP2D6 inhibitor. The manufacturer recommends avoidance of paroxetine and consideration of alternative SSRI antidepressants when oral metoclopramide is used in patients with diabetic gastroparesis. Healthy patients given 20 mg of metoclopramide and a strong CYP2D6 inhibitor for 8 days had a 40% and 90% increase in metoclopramide Cmax and AUC, respectively, compared to patients who received metoclopramide alone. Additionally, concomitant use of metoclopramide and SSRIs such as paroxetine may increase the risk for serotonin syndrome. In rare cases postmarketing, NMS-like symptoms, which may overlap with serotonin syndrome symptoms, have been reported with metoclopramide when used with serotonergic agents.
Metoprolol: (Moderate) Paroxetine impairs metabolism of the hepatic CYP2D6 isoenzyme pathway at therapeutic doses, resulting in substantial increases in concentrations of other drugs metabolized via the same pathway, including metoprolol. Clinicians should use paroxetine cautiously with metoprolol; downward dose adjustments of the beta-blocker may be required if paroxetine is initiated; alternatively an upward dose adjustment of the beta blocker may be needed if paroxetine is discontinued. Patients should be advised to report increased effects of these medications, including hypotension or increased dizziness to their health care professional.
Metoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Paroxetine impairs metabolism of the hepatic CYP2D6 isoenzyme pathway at therapeutic doses, resulting in substantial increases in concentrations of other drugs metabolized via the same pathway, including metoprolol. Clinicians should use paroxetine cautiously with metoprolol; downward dose adjustments of the beta-blocker may be required if paroxetine is initiated; alternatively an upward dose adjustment of the beta blocker may be needed if paroxetine is discontinued. Patients should be advised to report increased effects of these medications, including hypotension or increased dizziness to their health care professional.
Mexiletine: (Moderate) Paroxetine impairs metabolism of the cytochrome P-450 isoenzyme CYP2D6 pathway at therapeutic doses. Although no clinical data are available, paroxetine should be used cautiously in patients receiving mexiletine since this antiarrhythmic is metabolized by this isozyme. Inhibition of CYP2D6 can result in increased concentrations of drugs metabolized via the same pathway, including mexiletine, which may increase the risk of side effects or proarrhythmia.
Milnacipran: (Major) Because of the potential risk and severity of serotonin syndrome, concurrent use of milnacipran with other drugs that have serotonergic properties, such as the selective serotonin reuptake inhibitors (SSRIs), should generally be avoided. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome is suspected, milnacipran and concurrent serotonergic agents should be discontinued.
Mirabegron: (Moderate) Mirabegron is a moderate CYP2D6 substrate and inhibitor. Exposure of drugs metabolized by CYP2D6 such as paroxetine may be increased when co-administered with mirabegron. Paroxetine is a substrate and inhibitor of CYP2D6. Mirabegron exposure may also increase. Therefore, appropriate monitoring and dose adjustment may be necessary.
Mirtazapine: (Moderate) Coadministration of paroxetine and mirtazapine may increase the risk for serotonin syndrome. Cases of serotonin syndrome have been reported when mirtazapine has been administered with other selective serotonin reuptake inhibitors (SSRIs). Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome. If serotonin syndrome occurs, serotonergic agents should be discontinued and appropriate medical treatment should be implemented.
Monoamine oxidase inhibitors: (Contraindicated) Due to the risk of serotonin syndrome, monoamine oxidase inhibitors (MAOIs) intended to treat psychiatric disorders are contraindicated for use with selective serotonin reuptake inhibitors (SSRIs). MAOIs should not be used within 5 weeks of discontinuing treatment with fluoxetine or within 14 days of discontinuing treatment with other SSRIs. Conversely, SSRIs should not be initiated within 14 days of stopping an MAOI. Monitor the patient for serotonin-related effects during therapy transitions.
Moricizine: (Major) Paroxetine impairs metabolism of the cytochrome P-450 isoenzyme CYP2D6 pathway at therapeutic doses. Although no clinical data are available, paroxetine should be used cautiously in patients receiving type IC antiarrhythmics and mexiletine since these antiarrhythmics are metabolized by this isozyme. Inhibition of CYP2D6 can result in increased concentrations of Class IC antiarrhythmics which may increase the risk of side effects or proarrhythmia.
Morphine: (Moderate) If concomitant use of morphine and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Morphine; Naltrexone: (Moderate) If concomitant use of morphine and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Nalbuphine: (Moderate) If concomitant use of nalbuphine and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Naratriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering naratriptan with selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists ("triptans") and SSRIs. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly after initiation of SSRI treatment or any dose increases. Discontinue serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Nebivolol: (Major) Avoid the concomitant use of nebivolol and paroxetine. Nebivolol is metabolized by CYP2D6. Although data are lacking, CYP2D6 inhibitors, such as paroxetine, could potentially increase nebivolol plasma concentrations via CYP2D6 inhibition; the clinical significance of this potential interaction is unknown, but an increase in adverse effects is possible. If these drugs are coadministered, patients should be monitored for increased toxicity as well as increased therapeutic effect.
Nebivolol; Valsartan: (Major) Avoid the concomitant use of nebivolol and paroxetine. Nebivolol is metabolized by CYP2D6. Although data are lacking, CYP2D6 inhibitors, such as paroxetine, could potentially increase nebivolol plasma concentrations via CYP2D6 inhibition; the clinical significance of this potential interaction is unknown, but an increase in adverse effects is possible. If these drugs are coadministered, patients should be monitored for increased toxicity as well as increased therapeutic effect.
Nefazodone: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when coadministering drugs that have serotonergic properties such as nefazodone and paroxetine. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. At least one case report of serotonin syndrome from the concurrent use of nefazodone and a selective serotonin reuptake inhibitor (i.e., paroxetine) has been published. Additionally, when a 200 mg dose of nefazodone was administered to subjects who had been receiving fluoxetine for 1 week, there was an increased incidence of transient serotonin-related adverse events. If serotonin syndrome occurs, all serotonergic agents should be discontinued and appropriate medical treatment should be implemented.
Netupitant, Fosnetupitant; Palonosetron: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering palonosetron with other drugs that have serotonergic properties such as paroxetine. If serotonin syndrome is suspected, discontinue palonosetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death.
Nirmatrelvir; Ritonavir: (Major) A dose reduction of paroxetine may be necessary during co-administration of ritonavir. Concurrent use of CYP2D6 substrates, such as paroxetine, with ritonavir could result in increases (up to 2-fold) in the AUC of paroxetine. Paroxetine is metabolized by the hepatic isoenzyme CYP2D6; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Nitroglycerin: (Minor) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as antidepressants. Patients should be monitored more closely for hypotension if nitroglycerin is used concurrently with antidepressants.
Nonsteroidal antiinflammatory drugs: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and nonsteroidal antiinflammatory drugs (NSAIDs) may increase the risk of bleeding, including an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of NSAIDs. Additionally, NSAIDs impair the gastric mucosa defenses by inhibiting prostaglandin formation. A cohort study in more than 26,000 patients found that SSRI use alone increased the risk for serious GI bleed by 3.6-fold; when an SSRI was combined with NSAIDs, the risk was increased by more than 12.2-fold. The absolute risk of GI bleed from concomitant therapy with NSAIDs and a SSRI was low (17/4107 patients).
Nortriptyline: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of nortriptyline, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and nortriptyline may exhibit significant anticholinergic effects that may be additive during concurrent use.
Olanzapine: (Major) Concurrent use of paroxetine and olanzapine may result in additive anticholinergic effects, such as urinary retention, constipation, blurred vision, and xerostomia. In addition, paroxetine is a potent inhibitor of CYP2D6, which is a minor isoenzyme pathway for the metabolism of olanzapine. Adverse effects of olanzapine that may become evident include fatigue, dizziness, weight gain, prolactin elevation, orthostatic hypotension, sedation, or extrapyramidal symptoms. In addition, olanzapine is associated with a possible risk of QT prolongation and should be used cautiously with strong CYP2D6 inhibitors such as paroxetine.
Olanzapine; Fluoxetine: (Major) Concurrent use of paroxetine and olanzapine may result in additive anticholinergic effects, such as urinary retention, constipation, blurred vision, and xerostomia. In addition, paroxetine is a potent inhibitor of CYP2D6, which is a minor isoenzyme pathway for the metabolism of olanzapine. Adverse effects of olanzapine that may become evident include fatigue, dizziness, weight gain, prolactin elevation, orthostatic hypotension, sedation, or extrapyramidal symptoms. In addition, olanzapine is associated with a possible risk of QT prolongation and should be used cautiously with strong CYP2D6 inhibitors such as paroxetine. (Major) Due to the similarity in pharmacology of fluoxetine and paroxetine and the potential for serious adverse reactions, including serotonin syndrome, these selective serotonin reuptake inhibitors (SSRIs) should not be administered together. It is advisable to monitor for signs and symptoms of serotonin syndrome during an overlapping transition from one SSRI to another SSRI. In addition, because fluoxetine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes (TdP), concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Olanzapine; Samidorphan: (Major) Concurrent use of paroxetine and olanzapine may result in additive anticholinergic effects, such as urinary retention, constipation, blurred vision, and xerostomia. In addition, paroxetine is a potent inhibitor of CYP2D6, which is a minor isoenzyme pathway for the metabolism of olanzapine. Adverse effects of olanzapine that may become evident include fatigue, dizziness, weight gain, prolactin elevation, orthostatic hypotension, sedation, or extrapyramidal symptoms. In addition, olanzapine is associated with a possible risk of QT prolongation and should be used cautiously with strong CYP2D6 inhibitors such as paroxetine.
Oliceridine: (Moderate) Monitor patients closely for respiratory depression and sedation at frequent intervals and base subsequent doses on the patient's severity of pain and response to treatment if concomitant administration of oliceridine and paroxetine is necessary; less frequent dosing of oliceridine may be required. Concomitant use of oliceridine and paroxetine may increase the plasma concentration of oliceridine, resulting in increased or prolonged opioid effects. If paroxetine is discontinued, consider increasing the oliceridine dose until stable drug effects are achieved and monitor for evidence of opioid withdrawal. Oliceridine is a CYP2D6 substrate and paroxetine is a strong CYP2D6 inhibitor. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Ombitasvir; Paritaprevir; Ritonavir: (Major) A dose reduction of paroxetine may be necessary during co-administration of ritonavir. Concurrent use of CYP2D6 substrates, such as paroxetine, with ritonavir could result in increases (up to 2-fold) in the AUC of paroxetine. Paroxetine is metabolized by the hepatic isoenzyme CYP2D6; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Ondansetron: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as paroxetine. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. In addition, because ondansetron is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Oritavancin: (Moderate) Paroxetine is metabolized by CYP2D6; oritavancin is a weak CYP2D6 inducer. Plasma concentrations and efficacy of paroxetine may be reduced if these drugs are administered concurrently.
Orphenadrine: (Moderate) Additive anticholinergic effects may be seen when drugs with anticholinergic properties, like paroxetine and orphenadrine, are used concomitantly. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation.
Oxybutynin: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Oxycodone: (Moderate) If concomitant use of oxycodone and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Oxymorphone: (Moderate) If concomitant use of oxymorphone and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Ozanimod: (Major) Coadministration of ozanimod with paroxetine is not recommended due to the potential for hypertensive crisis and serotonin syndrome. If coadministration is necessary, closely monitor patients for hypertension and serotonergic effects. An active metabolite of ozanimod inhibits MAO-B, which may increase the potential for hypertensive crisis or serotonin syndrome. Paroxetine may increase blood pressure or sertonergic side effects by increasing serotonin concentrations.
Paliperidone: (Minor) Paroxetine is a potent inhibitor of CYP2D6, which may result in decreased clearance of partial CYP2D6 substrates such as paliperidone. Decreased metabolism of paliperidone may lead to clinically important adverse reactions such as extrapyramidal symptoms. In addition, paliperidone is associated with a risk for QT prolongation and torsade de pointes (TdP), and should be used cautiously with potent CYP2D6 inhibitors such as paroxetine. In one study of healthy subjects, paliperidone exposure was an average of 16% higher in extensive metabolizers of CYP2D6 who were receiving paroxetine 20 mg/day concurrently. The clinical significance of this interaction is unknown.
Palonosetron: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering palonosetron with other drugs that have serotonergic properties such as paroxetine. If serotonin syndrome is suspected, discontinue palonosetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death.
Peginterferon Alfa-2b: (Moderate) Monitor for adverse effects associated with increased exposure to paroxetine if peginterferon alfa-2b is coadministered. Peginterferon alfa-2b is a CYP2D6 inhibitor, while paroxetine is a CYP2D6 substrate.
Pentamidine: (Moderate) Pentamidine is a substrate of CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because pentamidine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Pentazocine: (Major) Because of the potential risk and severity of serotonin syndrome reactions, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as pentazocine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome occurs, discontinue the offending agent(s) and institute appropriate therapy.
Pentazocine; Naloxone: (Major) Because of the potential risk and severity of serotonin syndrome reactions, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as pentazocine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome occurs, discontinue the offending agent(s) and institute appropriate therapy.
Pentosan: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and pentosan, which has weak anticoagulant properties. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Pergolide: (Moderate) Use paroxetine and ergot alkaloids together with caution due to a potential for serotonin syndrome. Weakness, hyperreflexia, and incoordination have been reported rarely when ergot alkaloids or other serotonin agonists have been coadministered with SSRIs, which may be indicative of serotonin excess. If serotonin syndrome occurs, discontinue the offending agents and institute appropriate treatment.
Perphenazine: (Moderate) Substantial increases in concentrations of phenothiazines, such as perphenazine, may occur due to CYP2D6 inhibition by paroxetine, which may increase the risk of adverse effects such as CNS depression or extrapyramidal symptoms. In addition, because perphenazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. Additive anticholinergic effects are also possible.
Perphenazine; Amitriptyline: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of amitriptyline, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and amitriptyline may exhibit significant anticholinergic effects that may be additive during concurrent use. (Moderate) Substantial increases in concentrations of phenothiazines, such as perphenazine, may occur due to CYP2D6 inhibition by paroxetine, which may increase the risk of adverse effects such as CNS depression or extrapyramidal symptoms. In addition, because perphenazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. Additive anticholinergic effects are also possible.
Phenelzine: (Contraindicated) Due to the risk of serotonin syndrome, monoamine oxidase inhibitors (MAOIs) intended to treat psychiatric disorders are contraindicated for use with selective serotonin reuptake inhibitors (SSRIs). MAOIs should not be used within 5 weeks of discontinuing treatment with fluoxetine or within 14 days of discontinuing treatment with other SSRIs. Conversely, SSRIs should not be initiated within 14 days of stopping an MAOI. Monitor the patient for serotonin-related effects during therapy transitions.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Phentermine: (Moderate) Use phentermine and selective serotonin reuptake inhibitors (SSRIs) together with caution due to a potential for serotonin syndrome. Monitor weight, cardiovascular status, and for potential serotonergic adverse effects. Phentermine is related to the amphetamines, and there has been historical concern that phentermine might exhibit potential to cause serotonin syndrome when combined with serotonergic agents. However, recent data suggest that phentermine's effect on MAO inhibition and serotonin augmentation is minimal at therapeutic doses and some large controlled clinical studies have allowed patients to start phentermine-based therapy for obesity along with their SSRI as long as the antidepressant dose had been stable for at least 3 months prior. Such therapy was generally well-tolerated, especially at lower phentermine doses. Because depression and obesity often coexist, the study data may be important to providing optimal co-therapies.
Phentermine; Topiramate: (Moderate) Concurrent use of topiramate and drugs that affect platelet function such as selective serotonin reuptake inhibitors (SSRIs) like paroxetine may increase the risk of bleeding. In a pooled analysis of placebo-controlled trials, bleeding was more frequently reported in patients receiving topiramate (4.5%) compared to placebo (2 to 3%). In those with severe bleeding events, patients were often taking drugs that cause thrombocytopenia or affect platelet function or coagulation. (Moderate) Use phentermine and selective serotonin reuptake inhibitors (SSRIs) together with caution due to a potential for serotonin syndrome. Monitor weight, cardiovascular status, and for potential serotonergic adverse effects. Phentermine is related to the amphetamines, and there has been historical concern that phentermine might exhibit potential to cause serotonin syndrome when combined with serotonergic agents. However, recent data suggest that phentermine's effect on MAO inhibition and serotonin augmentation is minimal at therapeutic doses and some large controlled clinical studies have allowed patients to start phentermine-based therapy for obesity along with their SSRI as long as the antidepressant dose had been stable for at least 3 months prior. Such therapy was generally well-tolerated, especially at lower phentermine doses. Because depression and obesity often coexist, the study data may be important to providing optimal co-therapies.
Phenytoin: (Moderate) Monitor for decreased clinical efficacy of both drugs during coadministration of paroxetine and phenytoin; dosage adjustments may be necessary. Coadministration may result in decreased exposure of both drugs. At steady state, paroxetine exposure was reduced by 50% and phenytoin exposure was reduced by 12% during coadministration.
Pimozide: (Contraindicated) Pimozide is contraindicated for use with selective serotonin reuptake inhibitors (SSRIs) due to an increased risk of QT prolongation and torsade de pointes (TdP). Pimozide is thought to be primarily metabolized through CYP3A4, and to a lesser extent, CYP1A2 and CYP2D6. Elevated plasma concentrations of pimozide occurring through inhibition of one or more of these isoenzymes by SSRIs can lead to QT prolongation, ventricular arrhythmias, and sudden death. Additionally, most SSRIs are also associated with QT prolongation, further increasing the risk of additive QT prolongation.
Pirfenidone: (Moderate) Pirfenidone is primarily metabolized by CYP1A2 with minor contributions from other CYP isoenzymes including CYP2D6. Paroxetine is a potent inhibitor of CYP2D6. Because pirfenidone is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events and should be approached with caution.
Pitolisant: (Major) Initiate pitolisant at 8.9 mg once daily in patients taking paroxetine; increase pitolisant after 7 days to a maximum dosage of 17.8 mg once daily. If paroxetine is initiated in a patient on a stable dose of pitolisant, reduce the pitolisant dose by half. Pitolisant is a CYP2D6 substrate; paroxetine is a strong CYP2D6 inhibitor. Coadministration of paroxetine increased pitolisant exposure by 2.2-fold.
Prasugrel: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving prasugrel. Patients should be instructed to monitor for signs and symptoms of bleeding while taking an SSRI concurrently with an antiplatelet medication and to promptly report any bleeding events to the practitioner.
Procarbazine: (Major) Procarbazine is a weak monoamine oxidase inhibitor (MAOI). Although procarbazine appears to be less likely than other MAOIs to produce serious drug interactions, clinicians should avoid the use of selective serotonin reuptake inhibitors (SSRIs) in patients receiving MAOIs. Fatalities have been reported when fluoxetine was administered to patients receiving MAOIs. Confusion, seizures, severe hypertension, and other, less severe symptoms have also been reported with this drug combination. Non-selective MAOIs inhibit both MAO types A and B. Since serotonin is metabolized by MAO type A, it is thought that this drug interaction may lead to serotonin syndrome or neuroleptic malignant syndrome-like reactions. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. At least 2 weeks should elapse between the discontinuation of MAOI therapy and the start of therapy with an SSRI except fluoxetine. At least 5 weeks should elapse between the discontinuation of fluoxetine therapy and commencement of MAOI therapy. This 5-week period is needed because of the long half-lives of fluoxetine and its principle metabolite norfluoxetine.
Prochlorperazine: (Moderate) Substantial increases in concentrations of phenothiazines may occur due to CYP2D6 inhibition by paroxetine. which may increase the risk of adverse effects, including extrapyramidal symptoms or QT prolongation. Phenothiazines with a possible risk of QT prolongation include prochlorperazine. Additive anticholinergic effects are also possible.
Promethazine: (Moderate) Promethazine is a substrate for CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because promethazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. In addition, both paroxetine and promethazine exhibit anticholinergic effects that may be additive during combined therapy. The risk of other adverse effects of promethazine may also be increased, including sedation and extrapyramidal symptoms.
Promethazine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with paroxetine. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. In addition, paroxetine inhibits CYP2D6 and may increase systemic dextromethorphan exposure. Increased dextromethorphan concentrations may result in adverse effects consistent with the serotonin syndrome. (Moderate) Promethazine is a substrate for CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because promethazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. In addition, both paroxetine and promethazine exhibit anticholinergic effects that may be additive during combined therapy. The risk of other adverse effects of promethazine may also be increased, including sedation and extrapyramidal symptoms.
Promethazine; Phenylephrine: (Moderate) Promethazine is a substrate for CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because promethazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. In addition, both paroxetine and promethazine exhibit anticholinergic effects that may be additive during combined therapy. The risk of other adverse effects of promethazine may also be increased, including sedation and extrapyramidal symptoms.
Propafenone: (Major) Paroxetine impairs metabolism of the cytochrome P-450 isoenzyme CYP2D6 pathway at therapeutic doses. Although no clinical data are available, paroxetine should be used cautiously in patients receiving type IC antiarrhythmics and mexiletine since these antiarrhythmics are metabolized by this isozyme. Inhibition of CYP2D6 can result in increased concentrations of Class IC antiarrhythmics which may increase the risk of side effects or proarrhythmia.
Propantheline: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Propranolol: (Minor) Paroxetine impairs metabolism of the hepatic CYP2D6 isoenzyme pathway at therapeutic doses, resulting in substantial increases in concentrations of other drugs metabolized via the same pathway, including propranolol. Clinicians should use paroxetine cautiously with propranolol; downward dose adjustments of the beta-blocker may be required if paroxetine is initiated; alternatively an upward dose adjustment of the beta blocker may be needed if paroxetine is discontinued. Patients should be advised to report increased effects of these medications, including hypotension or increased dizziness to their health care professional.
Propranolol; Hydrochlorothiazide, HCTZ: (Minor) Paroxetine impairs metabolism of the hepatic CYP2D6 isoenzyme pathway at therapeutic doses, resulting in substantial increases in concentrations of other drugs metabolized via the same pathway, including propranolol. Clinicians should use paroxetine cautiously with propranolol; downward dose adjustments of the beta-blocker may be required if paroxetine is initiated; alternatively an upward dose adjustment of the beta blocker may be needed if paroxetine is discontinued. Patients should be advised to report increased effects of these medications, including hypotension or increased dizziness to their health care professional.
Protriptyline: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of protriptyline, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and protriptyline may exhibit significant anticholinergic effects that may be additive during concurrent use.
Pseudoephedrine; Triprolidine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as triprolidine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Pyrilamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as pyrilamine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Quetiapine: (Major) Because of the potential risk and severity of serotonin syndrome or neuroleptic malignant syndrome-like reactions, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with drugs that are dopamine antagonists such as quetiapine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. Patients receiving quetiapine and an SSRI should be monitored for the emergence of serotonin syndrome, neuroleptic malignant syndrome-like reactions, or other adverse effects.
Quinidine: (Moderate) Quinidine inhibits CYP2D6 and may theoretically increase concentrations of other drugs metabolized by this enzyme. Caution is recommended when administering quinidine with CYP2D6 substrates, including paroxetine.
Quinine: (Major) Both paroxetine and quinine are substrates of CYP2D6. In addition, quinine is a moderate inhibitor of CYP2D and paroxetine is a potent inhibitor of CYP2D6. One or both medications may inhibit the metabolism of the other. Patients should be monitored for an increase in adverse effects of paroxetine (e.g., serotonin syndrome, anticholinergic effects) or quinine (e.g., QT prolongation) during concurrent therapy. In addition, because quinine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Ranolazine: (Moderate) Monitor for adverse effects of paroxetine (e.g., serotonin syndrome) and ranolazine (e.g., QT prolongation) during coadministration. In theory, ranolazine may reduce the metabolism of paroxetine, and paroxetine may reduce the metabolism of ranolazine, increasing the risk for adverse effects associated with either drug. Both ranolazine and paroxetine are substrates of CYP2D6. Ranolazine is a moderate inhibitor of CYP2D6 and paroxetine is a potent inhibitor of CYP2D6. Because ranolazine is primarily metabolized by CYP3A4, inhibition of a single enzyme, such as CYP2D6, may not significantly decrease ranolazine clearance.
Rasagiline: (Major) It is recommended to avoid concurrent use of rasagiline and selective serotonin reuptake inhibitors (SSRIs). Severe CNS toxicity with hyperpyrexia has been reported during concurrent use of antidepressants and selective or non-selective MAOIs. During postmarketing use of rasagiline, non-fatal cases of serotonin syndrome have been reported during concomitant antidepressant administration. At least 2 weeks should elapse between stopping rasagiline treatment and beginning therapy with any SSRI. Conversely, when discontinuing an SSRI, it is advisable to wait the length of 4 to 5 half-lives of the individual agent being discontinued prior to initiation with rasagiline. At least 5 weeks should elapse between the discontinuation of fluoxetine therapy and initiation of rasagiline. If coadministration of rasagiline and fluvoxamine is required, do not exceed a rasagiline dose of 0.5 mg once daily. Rasagiline is primarily metabolized by CYP1A2; fluvoxamine is a strong CYP1A2 inhibitor. When rasagiline was administered with another strong CYP1A2 inhibitor, the AUC of rasagiline increased by 83%.
Remifentanil: (Moderate) If concomitant use of remifentanil and selective serotonin reuptake inhibitors (SSRIs) is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Reteplase, r-PA: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving thrombolytic agents. Patients should be closely monitored for signs and symptoms of bleeding when a thrombolytic agent is administered with an SSRI.
Risperidone: (Major) Initiate risperidone at a reduced dose in patients receiving paroxetine as increased plasma concentrations of risperidone and toxicity may occur. Do not exceed 8 mg PO per day of risperidone if these drugs are coadministered. For the long-acting risperidone injection, the current adult dosage should be closely monitored when paroxetine is initiated or discontinued. An adjustment of the dose may be required. Risperidone is a CYP2D6 substrate; paroxetine is a strong CYP2D6 inhibitor. Daily dosing of paroxetine 20 mg PO in patients stabilized on risperidone (4 to 8 mg/day) increased mean plasma concentrations of risperidone roughly 4-fold, decreased 9-hydroxyrisperidone concentrations approximately 10%, and increased concentrations of the active moiety (the sum of risperidone plus 9-hydroxyrisperidone) approximately 1.4-fold. Other data suggest that daily administration of paroxetine increases plasma concentrations of risperidone 3- to 9-fold.
Ritonavir: (Major) A dose reduction of paroxetine may be necessary during co-administration of ritonavir. Concurrent use of CYP2D6 substrates, such as paroxetine, with ritonavir could result in increases (up to 2-fold) in the AUC of paroxetine. Paroxetine is metabolized by the hepatic isoenzyme CYP2D6; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
Rivaroxaban: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like rivaroxaban. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Rizatriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering rizatriptan with selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists ("triptans") and SSRIs. Some patients had used the combination previously without incident when serotonin syndrome occurred. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly after the initiation of the SSRI or dose increases. Discontinue serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Rolapitant: (Major) Use caution if paroxetine and rolapitant are used concurrently, and monitor for paroxetine-related adverse effects. Paroxetine is a CYP2D6 substrate and rolapitant is a moderate CYP2D6 inhibitor; the inhibitory effect of rolapitant is expected to persist beyond 28 days for an unknown duration. Exposure to another CYP2D6 substrate, following a single dose of rolapitant increased about 3-fold on Days 8 and Day 22. The inhibition of CYP2D6 persisted on Day 28 with a 2.3-fold increase in the CYP2D6 substrate concentrations, the last time point measured.
Safinamide: (Major) The concurrent use of selective serotonin reuptake inhibitors (SSRIs) and monoamine oxidase inhibitors (MAOIs) is generally avoided; however, the manufacturer of safinamide recommends monitoring for serotonin syndrome and using the lowest effective dose of the SSRI during concurrent use. During clinical trial evaluation of safinamide, 1 case of serotonin syndrome occurred during co-administration with an SSRI. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death.
Salsalate: (Moderate) The combined use of selective serotonin reuptake inhibitors (SSRIs) and aspirin, ASA or other salicylates which affect hemostasis may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. A cohort study in > 26,000 patients found that SSRI use alone increased the risk for serious GI bleed by 3.6-fold; when an SSRI was combined with aspirin the risk was increased by > 5-fold. The absolute risk of GI bleed from concomitant therapy with aspirin and a SSRI was low (20/2640 patients) in this cohort study and the clinician may determine that the combined use of these drugs is appropriate.
Scopolamine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Selegiline: (Contraindicated) Selective serotonin reuptake inhibitors (SSRIs) are contraindicated for use with selegiline, a selective monoamine oxidase type B inhibitor (MAO-B inhibitor). At least 14 days should elapse between discontinuation of selegiline and initiation of treatment with an SSRI. With the exception of fluoxetine, a time period equal to 4 to 5 half-lives of the SSRI or any active metabolite should elapse after discontinuing treatment with the SSRI and before starting therapy with selegiline. Because of the long half-life of fluoxetine and its active metabolite, at least 5 weeks should elapse between discontinuation of fluoxetine and initiation of treatment with selegiline. Serotonin syndrome has occurred in patients receiving selective MAO-B inhibitors and serotonin-augmenting antidepressants simultaneously. Monitor for serotonergic side effects during therapy transitions.
Sertraline: (Major) Due to the similarity in pharmacology of sertraline and paroxetine and the potential for serious adverse reactions, including serotonin syndrome, selective serotonin reuptake inhibitors (SSRIs) should not be administered together. It is advisable to monitor for signs and symptoms of serotonin syndrome during an overlapping transition from one SSRI to another SSRI.
Sibutramine: (Major) Sibutramine is a serotonin reuptake inhibitor. Because of the potential risk and severity of serotonin syndrome or neuroleptic malignant syndrome-like reactions, caution should be observed when administering sibutramine with other drugs that have serotonergic properties such as selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. In addition, in vitro studies indicate that metabolism of sibutramine is mediated through CYP3A4. Theoretically, the metabolism of sibutramine may be decreased as a result of CYP3A4 inhibition by fluoxetine or fluvoxamine. Patients receiving sibutramine in combination with an SSRI should be monitored for the emergence of serotonin syndrome, neuroleptic malignant syndrome-like reactions, or other adverse effects.
Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Moderate) Use caution when prescribing sodium picosulfate; magnesium oxide; anhydrous citric acid in patients taking concomitant medications that are known to induce Antidiuretic Hormone Secretion (SIADH), such as tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), antipsychotics and carbamazepine, as these drugs may increase the risk of water retention and/or electrolyte imbalance.
St. John's Wort, Hypericum perforatum: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when coadministering paroxetine and St. John's Wort. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose increases. If serotonin syndrome occurs, serotonergic drugs should be discontinued and appropriate medical treatment should be initiated.
Streptokinase: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving thrombolytic agents. Patients should be closely monitored for signs and symptoms of bleeding when a thrombolytic agent is administered with an SSRI.
Sufentanil: (Moderate) If concomitant use of sufentanil and paroxetine is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Sumatriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering sumatriptan with selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists ("triptans") and SSRIs. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly after initiation of SSRI treatment or any dose increases. Discontinue serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Sumatriptan; Naproxen: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering sumatriptan with selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists ("triptans") and SSRIs. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly after initiation of SSRI treatment or any dose increases. Discontinue serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Tamoxifen: (Moderate) Monitor for decreased efficacy of tamoxifen if coadministration with paroxetine is necessary. Tamoxifen is metabolized by CYP2D6 to endoxifen and 4-hydroxytamoxifen, both of which are minor metabolites but have 100-fold greater affinity for the estrogen receptor and 30- to 100-fold greater potency in suppressing estrogen-dependent cell proliferation than tamoxifen. Paroxetine is a strong CYP2D6 inhibitor. In one study, the mean steady-state plasma concentration of endoxifen in CYP2D6 normal metabolizers who were not receiving CYP2D6 inhibitors were 3.6-fold higher compared to normal metabolizers who were receiving strong CYP2D6 inhibitors (e.g., paroxetine); plasma levels in CYP2D6 normal metabolizers receiving strong CYP2D6 inhibitors were similar to levels observed in CYP2D6 poor metabolizers taking no CYP2D6 inhibitors. In another study, the mean steady-state endoxifen plasma concentration was significantly reduced in patients taking CYP2D6 inhibitors compared to those not taking concomitant CYP2D6 inhibitors. Some studies have shown that the efficacy of tamoxifen may be reduced when concomitant drugs decrease the levels of potent active metabolites; however, others have failed to demonstrate such an effect. The clinical significance is not well established.
Tamsulosin: (Moderate) Use caution when administering tamsulosin with a strong CYP2D6 inhibitor such as paroxetine. Tamsulosin is extensively metabolized by CYP2D6 hepatic enzymes. In clinical evaluation, concomitant treatment with paroxetine resulted in an increase in the Cmax and AUC of tamsulosin by a factor of 1.3 and 1.6, respectively. If concomitant use in necessary, monitor patient closely for increased side effects.
Tapentadol: (Moderate) If concomitant use of tapentadol and selective serotonin reuptake inhibitors (SSRIs) is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Tedizolid: (Minor) Caution is warranted with the concurrent use of tedizolid and selective serotonin reuptake inhibitors (SSRIs) due to the theoretical risk of serotonin syndrome. Animal studies did not predict serotonergic effects; however, patients on concurrent SSRIs were excluded from clinical trials. Addtionally, tedizolid is an antibiotic that is also a weak reversible, non-selective MAO inhibitor and monoamine oxidase type A deaminates serotonin; therefore, coadministration theoretically could lead to serious reactions including serotonin syndrome. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome has been reported in patients receiving either citalopram, escitalopram, fluoxetine, or paroxetine in combination with linezolid, which is structurally similar to tedizolid.
Tenecteplase: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving thrombolytic agents. Patients should be closely monitored for signs and symptoms of bleeding when a thrombolytic agent is administered with an SSRI.
Terbinafine: (Moderate) Systemic terbinafine inhibits hepatic isoenzyme CYP2D6, and thus may inhibit the clearance of drugs metabolized by this isoenzyme, such as selective serotonin reuptake inhibitors (SSRIs). The clinical relevance of the interaction is not known. Topical forms of terbinafine do not interact.
Tetrabenazine: (Major) The primary metabolites of tetrabenazine, alpha-dihydrotetrabenzaine (alpha-HTBZ) and beta-dihydrotetrabenazine (beta-HTBZ), are substrates for CYP2D6. Coadministration of 50 mg of tetrabenazine following 10 days of 20 mg of paroxetine, a potent CYP2D6 inhibitor, resulted in an increase in Cmax of approximately 30% and a 3-fold increase in AUC for alpha-HTBZ. The Cmax and AUC for beta-HTBZ increased 2.4-fold and 9-fold, respectively. The elimination half-life of alpha-HTBZ and beta-HTBZ was approximately 14 hours when tetrabenazine was given with paroxetine. When tetrabenazine is given with a strong inhibitor of CYP2D6 such as paroxetine, the maximum single dose of tetrabenazine should not exceed 25 mg and the daily dose should not exceed 50 mg. In addition, because tetrabenazine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events. During use of this combination, monitor for adverse effects associated with tetrabenazine such as QT prolongation, excess sedation, and extrapyramidal symptoms.
Theophylline, Aminophylline: (Major) Paroxetine has been reported to cause elevations of theophylline serum concentrations. Monitor aminophylline serum concentrations when paroxetine is given concurrently with aminophylline. Observe patients for signs or symptoms of aminophylline toxicity. (Major) Paroxetine has been reported to cause elevations of theophylline serum concentrations. The interaction has not been formally studied. It is recommended that theophylline serum concentrations be monitored when paroxetine is given concurrently with theophylline or aminophylline. Observe patients for signs or symptoms of theophylline toxicity.
Thioridazine: (Contraindicated) Thioridazine is contraindicated for use with paroxetine. Serum concentrations of thioridazine and its two active metabolites, mesoridazine and sulforidazine, may increase by up to three-fold through potent inhibition of CYP2D6 by paroxetine. Substantial increases in serum thioridazine concentrations may lead to QT prolongation, which is associated with serious ventricular arrhythmias, such as torsade de pointe and sudden death. In addition, the risk of extrapyramidal symptoms and anticholinergic effects is increased.
Thrombin Inhibitors: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and other drugs that affect coagulation like thrombin inhibitors. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Thrombolytic Agents: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving thrombolytic agents. Patients should be closely monitored for signs and symptoms of bleeding when a thrombolytic agent is administered with an SSRI.
Ticagrelor: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving prasugrel. Patients should be instructed to monitor for signs and symptoms of bleeding while taking an SSRI concurrently with an antiplatelet medication and to promptly report any bleeding events to the practitioner.
Ticlopidine: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication (e.g., gastrointestinal bleeding, ecchymoses, epistaxis, hematomas, petechiae, hemorrhage) in patients receiving platelet inhibitors (e.g., cilostazol, clopidogrel, dipyridamole, ticlopidine, platelet glycoprotein IIb/IIIa inhibitors). Patients should be instructed to monitor for signs and symptoms of bleeding while taking an SSRI concurrently with an antiplatelet medication and to promptly report any bleeding events to the practitioner.
Timolol: (Moderate) Timolol is significantly metabolized by CYP2D6 isoenzymes. CYP2D6 inhibitors, such as paroxetine, could theoretically impair timolol metabolism; the clinical significance of such interactions is unknown.
Tinzaparin: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and anticoagulants like low molecular weight heparins. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Tipranavir: (Moderate) Use caution when coadministering tipranavir and ritonavir with SSRIs, as increased SSRI concentrations may be seen. Patients should be monitored for increased SSRI adverse effects and the SSRI dose should be adjusted if necessary.
Tirofiban: (Moderate) Platelet aggregation may be impaired by SSRIs due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving platelet inhibitors. Monitor for signs and symptoms of bleeding.
Tolterodine: (Moderate) Paroxetine, a potent CYP2D6 inhibitor, may inhibit the metabolism of tolterodine, a CYP2D6 substrate. In a study assessing another potent CYP2D6 inhibitor (fluoxetine) and tolterodine, the metabolism of tolterodine immediate release was significantly decreased in CYP2D6 extensive metabolizers, resulting in a 4.8-fold increase in tolterodine AUC. There was a 52% decrease in Cmax and a 20% decrease in AUC of 5-hydroxymethyl tolterodine (5-HMT), the active metabolite of tolterodine. The sums of unbound serum concentrations of tolterodine and 5-HMT were only 25% higher during the interaction. Although the manufacturer requires no dose adjustment during concurrent use of tolterodine and fluoxetine, the kinetic and clinical effects of paroxetine use are unknown. Both drugs exhibit anticholinergic effects that may be additive. In addition, because tolterodine is a primary substrate of CYP2D6 and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Topiramate: (Moderate) Concurrent use of topiramate and drugs that affect platelet function such as selective serotonin reuptake inhibitors (SSRIs) like paroxetine may increase the risk of bleeding. In a pooled analysis of placebo-controlled trials, bleeding was more frequently reported in patients receiving topiramate (4.5%) compared to placebo (2 to 3%). In those with severe bleeding events, patients were often taking drugs that cause thrombocytopenia or affect platelet function or coagulation.
Tramadol: (Moderate) Monitor for reduced efficacy of tramadol, signs of opioid withdrawal, seizures, or serotonin syndrome if coadministration with paroxetine is necessary. If paroxetine is discontinued, consider a dose reduction of tramadol and frequently monitor for signs of respiratory depression and sedation. Tramadol is a CYP2D6 substrate and paroxetine is a CYP2D6 inhibitor. Concomitant use of tramadol with CYP2D6 inhibitors can increase the plasma concentration of tramadol and decrease the plasma concentration of the active metabolite M1. Since M1 is a more potent mu-opioid agonist, decreased M1 exposure could result in decreased therapeutic effects, and may result in signs and symptoms of opioid withdrawal in patients who have developed physical dependence to tramadol. Increased tramadol exposure can result in increased or prolonged therapeutic effects and increased risk for serious adverse events including seizures and serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Tramadol; Acetaminophen: (Moderate) Monitor for reduced efficacy of tramadol, signs of opioid withdrawal, seizures, or serotonin syndrome if coadministration with paroxetine is necessary. If paroxetine is discontinued, consider a dose reduction of tramadol and frequently monitor for signs of respiratory depression and sedation. Tramadol is a CYP2D6 substrate and paroxetine is a CYP2D6 inhibitor. Concomitant use of tramadol with CYP2D6 inhibitors can increase the plasma concentration of tramadol and decrease the plasma concentration of the active metabolite M1. Since M1 is a more potent mu-opioid agonist, decreased M1 exposure could result in decreased therapeutic effects, and may result in signs and symptoms of opioid withdrawal in patients who have developed physical dependence to tramadol. Increased tramadol exposure can result in increased or prolonged therapeutic effects and increased risk for serious adverse events including seizures and serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Tranylcypromine: (Contraindicated) Due to the risk of serotonin syndrome, monoamine oxidase inhibitors (MAOIs) intended to treat psychiatric disorders are contraindicated for use with selective serotonin reuptake inhibitors (SSRIs). MAOIs should not be used within 5 weeks of discontinuing treatment with fluoxetine or within 14 days of discontinuing treatment with other SSRIs. Conversely, SSRIs should not be initiated within 14 days of stopping an MAOI. Monitor the patient for serotonin-related effects during therapy transitions.
Trazodone: (Moderate) Coadministration of trazodone and paroxetine may increase the risk of serotonin syndrome. Serotonin syndrome has been reported with both drugs when taken alone, but especially when coadministered with other serotonergic agents. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome. Discontinue serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Trifluoperazine: (Moderate) Substantial increases in concentrations of phenothiazines may occur due to CYP2D6 inhibition by paroxetine, which may increase the risk of adverse effects, including extrapyramidal symptoms or QT prolongation. Phenothiazines with a possible risk of QT prolongation include trifluoperazine. Additive anticholinergic effects are also possible.
Trihexyphenidyl: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used concomitantly with anticholinergic agents. Adverse effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the specific anticholinergic used.
Trimipramine: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. In addition, paroxetine is a potent CYP2D6 inhibitor and may decrease the metabolism of trimipramine, a CYP2D6 substrate. Because there is a risk of QT prolongation and torsade de pointes (TdP) with tricyclics at elevated serum concentrations, coadministration should be approached with caution and close monitoring. Lastly, both paroxetine and trimipramine may exhibit significant anticholinergic effects that may be additive during concurrent use.
Triprolidine: (Moderate) Of the selective serotonin reuptake inhibiting antidepressants (SSRIs), paroxetine is considered the most anticholinergic. Additive anticholinergic effects may be seen when paroxetine is used with antihistamines having anticholinergic properties such as triprolidine. Patients should be informed to read non-prescription cough and cold product labels carefully for additional interacting antihistamines.
Tryptophan, 5-Hydroxytryptophan: (Major) Concurrent use of tryptophan and a selective serotonin reuptake inhibitor (SSRI) is not recommended. Since tryptophan is converted to serotonin, the use of tryptophan in patients receiving SSRIs could lead to serotonin excess and, potentially, serotonin syndrome. Discontinuation of tryptophan usually resolves symptoms.
Urokinase: (Moderate) Platelet aggregation may be impaired by selective serotonin reuptake inhibitors (SSRIs) due to platelet serotonin depletion, possibly increasing the risk of a bleeding complication in patients receiving thrombolytic agents. Patients should be closely monitored for signs and symptoms of bleeding when a thrombolytic agent is administered with an SSRI.
Valbenazine: (Major) Consider reducing the dose of valbenazine, based on tolerability, during co-administration with a strong CYP2D6 inhibitor, such as paroxetine. QT prolongation is not clinically significant at valbenazine concentrations expected with recommended dosing; however, concentrations of the active metabolite of valbenazine may be higher in patients taking a strong CYP2D6 inhibitor and QT prolongation may become clinically significant.
Valerian, Valeriana officinalis: (Moderate) Substances that act on the CNS, including psychoactive drugs, may theoretically interact with valerian, Valeriana officinalis. These interactions are probably pharmacodynamic in nature, or result from additive mechanisms of action. Persons taking medications such as SSRIs should discuss the use of herbal supplements with their health care professional prior to consuming these herbs. Patients should not abruptly stop taking their prescribed psychoactive medication.
Vasopressin, ADH: (Moderate) Monitor hemodynamics and adjust the dose of vasopressin as needed when used concomitantly with drugs suspected of causing syndrome of inappropriate antidiuretic hormone (SIADH), such as selective serotonin reuptake inhibitors. Use together may increase the pressor and antidiuretic effects of vasopressin.
Vemurafenib: (Moderate) Concomitant use of vemurafenib and paroxetine may result in increased paroxetine concentrations. Paroxetine is metabolized by CYP2D6 and vemurafenib is a weak CYP2D6 inhibitor. Monitor patients for toxicity.
Venlafaxine: (Major) Due to similarity of pharmacology and the potential for serotonin syndrome, selective serotonin reuptake inhibitors (SSRIs) should generally not be administered with serotonin norepinephrine reuptake inhibitors like venlafaxine. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome is suspected, venlafaxine, paroxetine, and concurrent serotonergic agents should be discontinued. In addition, because venlafaxine is a CYP2D6 substrate and has a possible risk of QT prolongation and torsade de pointes, concurrent use of a potent CYP2D6 inhibitor such as paroxetine may increase the risk of such events.
Vilazodone: (Major) Due to possible additive effects on serotonin concentrations, it is advisable to avoid combining selective serotonin reuptake inhibitors (SSRIs) such as paroxetine with vilazodone. Interactions between vilazodone and serotonergic agents can lead to serotonin syndrome. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Patients receiving vilazodone and paroxetine should be monitored for the emergence of serotonin syndrome, particularly during treatment initiation and during dosage increases. Vilazodone and paroxetine should be discontinued if serotonin syndrome occurs and supportive symptomatic treatment should be initiated.
Vorapaxar: (Moderate) Because vorapaxar inhibits platelet aggregation, a potential additive risk for bleeding exists if vorapaxar is given in combination with other agents that affect hemostasis such as selective serotonin reuptake inhibitors (SSRIs). Platelet aggregation may be impaired by SSRIs due to platelet serotonin depletion. In addition, fluoxetine and fluvoxamine are CYP3A4 inhibitors and coadministration with vorapaxar, a CYP3A4 substrate, may result in increased serum concentrations of vorapaxar. Increased exposure to vorapaxar may increase the risk of bleeding complications. Patients should be instructed to monitor for signs and symptoms of bleeding while taking a SSRI with vorapaxar and to promptly report any bleeding events.
Vortioxetine: (Major) Due to similarity of pharmacology and the potential for additive adverse effects, including serotonin syndrome, vortioxetine should generally not be co-administered with selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Monitor for serotonin syndrome during a transition from vortioxetine to an SSRI. If coadministration is necessary, the manufacturer recommends a reduction in the vortioxetine dose by one-half when strong inhibitors of CYP2D6 such as paroxetine are used since CYP2D6 is the primary isoenzyme responsible for the metabolism of vortioxetine to its inactive metabolite. The vortioxetine dose should be increased to the original level when the CYP2D6 inhibitor is discontinued.
Warfarin: (Moderate) Advise patients of the increased bleeding risk associated with the concomitant use of paroxetine and warfarin. Carefully monitor patients receiving warfarin therapy if paroxetine is initiated or discontinued. Some data suggest there may be a pharmacodynamic interaction that causes increased bleeding without a change in prothrombin time. Case reports and epidemiological studies have demonstrated an association between use of drugs that interfere with serotonin reuptake and gastrointestinal bleeding.
Ziprasidone: (Major) Because of the potential risk and severity of serotonin syndrome or neuroleptic malignant syndrome-like reactions, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with drugs that are dopamine antagonists such as ziprasidone. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. Patients receiving ziprasidone and an SSRI should be monitored for the emergence of serotonin syndrome, neuroleptic malignant syndrome-like reactions, or other adverse effects.
Zolmitriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering zolmitriptan with selective serotonin reuptake inhibitors (SSRIs). Serotonin syndrome has been reported during concurrent use of serotonin-receptor agonists ("triptans") and SSRIs. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly after initiation of SSRI treatment or any dose increases. Discontinue serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Zolpidem: (Moderate) Disorientation, delusions, or hallucinations have been reported rarely during co-administration of zolpidem and SSRIs (e.g., fluoxetine, sertraline, fluvoxamine). The duration of the visual hallucinations has ranged from 30 minutes to 7 hours. Data from a clinical study in which SSRI-treated patients were given immediate-release zolpidem revealed that four of the seven discontinuations during double-blind treatment with zolpidem (n = 95) were associated with impaired concentration, continuing or aggravated depression, and manic reaction. The mechanism for the interaction is thought to be pharmacodynamic in nature; therefore, a similar reaction is possible with other SSRIs such as paroxetine.

PREGNANCY AND LACTATION

Paroxetine should be administered to a breast-feeding mother with caution. In one small trial, mothers ingested up to 50 mg/day PO of paroxetine for more than 10 days. Paroxetine was excreted into the breast milk, but at low concentrations (less than 2 ng/mL). None of the breast-fed infants had detectable serum concentrations and none experienced adverse effects from the medication. Other SSRIs (e.g., fluoxetine) are excreted in breast milk and have been reported to increase infant irritability. The long-term effects of paroxetine on a breast-feeding infant are unknown. A pooled analysis found that maternal use of paroxetine, along with nortriptyline and sertraline, usually produced undetectable or low drug concentrations in infant serum and, therefore, may be the preferred antidepressants in breast-feeding mothers. Consider the benefits of breast-feeding, the risk of potential drug exposure, and the risk of an untreated or inadequately treated condition.

MECHANISM OF ACTION

The precise antidepressant effect of the selective serotonin reuptake inhibitors (SSRIs) is not fully understood, but involves selective serotonin reuptake blockade at the neuronal membrane, which enhances the actions of serotonin (5-HT). Initially, SSRIs increase availability of serotonin in the somatodendritic area through serotonin reuptake blockade at the serotonin transport pump. During long-term administration of SSRIs, serotonin autoreceptors are down-regulated and desensitized, allowing the neuron to increase serotonin release in the axon terminal synapses and increase its neuronal impulses. Because of the delay in therapeutic response to SSRIs, it is theorized that the change in the balance of serotonin receptors over time is an important mechanism of effect. The therapeutic action of SSRIs in treating anxiety disorders is thought to occur from potent central serotonin reuptake blockade although the exact mechanism is unknown. SSRIs exhibit less sedative, anticholinergic, and cardiovascular effects than do tricyclic antidepressants due to decreased binding to histaminergic, muscarinic, and alpha-adrenergic receptors. However, paroxetine is noted to have the most anticholinergic activity of all the SSRIs. The mechanism of action of paroxetine in the treatment of vasomotor symptoms associated with menopause is unknown.

PHARMACOKINETICS

Paroxetine formulations are administered orally. The drug is widely distributed, including into the CNS, with only 1% of paroxetine remaining in the plasma. Paroxetine is 93% to 95% bound to plasma protein; however, the drug does not displace other highly protein-bound drugs. Based on pharmacokinetic studies, the steady-state paroxetine exposure based on AUC is several-fold higher than with a single dose. The excess accumulation is a consequence of a saturable metabolic pathway. Paroxetine is extensively metabolized via oxidation, methylation and conjugation to several metabolites, none of which shows any appreciable pharmacological activity. Conjugates with glucuronic acid and sulfate predominate. Metabolism is achieved predominantly by CYP2D6. Due to saturation of CYP2D6 by paroxetine, the relationship between pharmacokinetics and dosage or duration of treatment is nonlinear. At steady-state, when the CYP2D6 is essentially saturated, paroxetine clearance becomes governed by CYP3A4, which, unlike CYP2D6, does not show evidence of saturation. The mean elimination half-life of the immediate-release paroxetine is approximately 21 hours while the elimination half-life for the controlled-release product is 15 to 20 hours. Excretion is mainly renal (about 62%), mostly as metabolites and about 2% as unchanged drug. Roughly 36% is excreted in the feces, mainly via the bile as metabolites.
 
Affected cytochrome P450 (CYP450) isoenzymes and drug transporters: CYP2D6
Paroxetine is a substrate and potent inhibitor of CYP2D6. In more than 90% of patients, CYP2D6 is saturated early in dosing with paroxetine (in roughly 10 to 14 days). Due to saturation of CYP2D6 by paroxetine, the relationship between pharmacokinetics and dosage or duration of treatment is nonlinear. At steady-state, when the CYP2D6 is essentially saturated, paroxetine clearance becomes governed by CYP3A4, which, unlike CYP2D6, does not show evidence of saturation. Paroxetine does not appear to inhibit other CYP isoenzymes, including CYP3A4, to any clinically significant degree.