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  • CLASSES

    Carbonic Anhydrase Inhibitors

    DEA CLASS

    Rx

    DESCRIPTION

    Oral carbonic anhydrase inhibitor
    For the treatment of primary hypokalemic or hyperkalemic periodic paralysis and related variants
    Associated with hypokalemia and metabolic acidosis

    COMMON BRAND NAMES

    Keveyis

    HOW SUPPLIED

    Keveyis Oral Tab: 50mg

    DOSAGE & INDICATIONS

    For the treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants.
    Oral dosage
    Adults

    Initially, 50 mg PO once daily or twice daily. The dose may be increased or decreased at weekly intervals based on clinical response, or sooner in the case of an adverse reaction. Max: 200 mg/day PO. Evaluate the need for continued therapy after 2 months of treatment.

    MAXIMUM DOSAGE

    Adults

    200 mg/day PO.

    Geriatric

    200 mg/day PO.

    Adolescents

    Safety and efficacy have not been established.

    Children

    Safety and efficacy have not been established.

    Infants

    Safety and efficacy have not been established.

    Neonates

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Dichlorphenamide is contraindicated for use in patients with hepatic insufficiency.

    Renal Impairment

    Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.

    ADMINISTRATION

    Oral Administration

    May be administered without regard to meals.

    STORAGE

    Keveyis:
    - Store at controlled room temperature (between 68 and 77 degrees F)

    CONTRAINDICATIONS / PRECAUTIONS

    Carbonic anhydrase inhibitor hypersensitivity, sulfonamide hypersensitivity

    Dichlorphenamide is contraindicated in patients with dichlorphenamide hypersensitivity or sulfonamide hypersensitivity. Dichlorphenamide is a carbonic anhydrase inhibitor and a sulfonamide derivative. Fatalities associated with the administration of sulfonamides have occurred because of adverse reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. Pulmonary involvement can occur in isolation or as part of a systemic reaction. Dichlorphenamide should be discontinued at the first appearance of skin rash or any sign of immune-mediatedor other life-threatening adverse reaction. Avoid use in patients who have exhibited prior carbonic anhydrase inhibitor hypersensitivity since cross-reactivity may occur.

    Hepatic disease, hepatic encephalopathy

    Dichlorphenamide is contraindicated in patients with hepatic disease, as therapy in patients with hepatic insufficiency may aggravate hepatic encephalopathy.

    Aspirin coadministration, metabolic acidosis

    Hyperchloremic non-anion gap metabolic acidosis can occur with the use of dichlorphenamide. The severity may increase with the concomitant use of other drugs that cause metabolic acidosis. This especially is true with high-dose aspirin coadministration. High-dose aspirin use with dichlorphenamide is contraindicated, as metabolic acidosis due to dichlorphenamide can increase the risk of salicylate toxicity. Such toxicity has been reported with concomitant use of dichlorphenamide and high-dose aspirin. Patients who take low-dose aspirin along with dichlorphenamide should be carefully monitored. In all patients, measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.

    Cushing's syndrome, hypokalemia, renal tubular acidosis (RTA)

    Dichlorphenamide use increases the excretion of potassium and can result in hypokalemia. The risk of dichlorphenamide-induced hypokalemia is greater when used in patients with conditions associated with hypokalemia (e.g., adrenocortical excess such as Cushing's syndrome, hyperchloremic metabolic acidosis, renal tubular acidosis (RTA) type 1 and 2) and in patients receiving other drugs that may cause hypokalemia. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.

    Pulmonary disease, respiratory acidosis

    Dichlorphenamide is contraindicated for use in patients with severe pulmonary disease. Concomitant use of dichlorphenamide in compensated patients with respiratory acidosis, such as in advanced lung diseases, may lead to respiratory decompensation. Dichlorphenamide may result in hyperchloremic non-anion gap metabolic acidosis, and patients with severe pulmonary disease are not able to increase alveolar ventilation to compensate for the metabolic acidosis.

    Geriatric

    Dichlorphenamide use increases the risk of falls; this risk is greater in the geriatric patient and in those patients receiving higher doses of dichlorphenamide. If falls occur during dichlorphenamide therapy, consider reducing the dose or discontinuing therapy.

    Labor, neonates, obstetric delivery, pregnancy

    There are no adequate data on the developmental risk associated with dichlorphenamide use during human pregnancy. Teratogenicity (limb reduction defects) was reported in rats receiving 17-times the maximum recommended human dose (MRHD) of 200 mg/day on a body surface area basis. A no-effect dose for adverse effects on embryofetal development has not been established. The effect of dichlorphenamide-induced metabolic acidosis has not been studied in pregnancy; however, metabolic acidosis in pregnancy (due to other causes) can cause decreased fetal growth, decreased fetal oxygenation, and fetal death. Pregnant patients should be monitored for metabolic acidosis and treated as in the nonpregnant state. Metabolic acidosis may affect the fetus' ability to tolerate labor and obstetric delivery. Neonates born to mothers treated with dichlorphenamide should be monitored for metabolic acidosis because of possible occurrence of transient metabolic acidosis following birth.

    Breast-feeding

    There are no data on the presence of dichlorphenamide in human milk, the effects on the breastfed infant, or the effects on milk production. Consider the developmental and health benefits of breast-feeding along with the mother's clinical need for dichlorphenamide and any potential adverse effects on the breast-fed infant from dichlorphenamide or the underlying maternal condition.

    ADVERSE REACTIONS

    Severe

    toxic epidermal necrolysis / Delayed / Incidence not known
    hepatic necrosis / Delayed / Incidence not known
    aplastic anemia / Delayed / Incidence not known
    Stevens-Johnson syndrome / Delayed / Incidence not known
    pancytopenia / Delayed / Incidence not known
    agranulocytosis / Delayed / Incidence not known
    seizures / Delayed / Incidence not known
    renal tubular necrosis / Delayed / Incidence not known
    heart failure / Delayed / Incidence not known

    Moderate

    confusion / Early / 11.0-11.0
    metabolic acidosis / Delayed / Incidence not known
    hypokalemia / Delayed / Incidence not known
    amnesia / Delayed / Incidence not known
    psychosis / Early / Incidence not known
    hallucinations / Early / Incidence not known
    dyspnea / Early / Incidence not known
    nephrolithiasis / Delayed / Incidence not known

    Mild

    paresthesias / Delayed / 44.0-44.0
    dysgeusia / Early / 14.0-14.0
    rash / Early / 8.0-8.0
    hypoesthesia / Delayed / 8.0-8.0
    lethargy / Early / 8.0-8.0
    headache / Early / 8.0-8.0
    fatigue / Early / 8.0-8.0
    pruritus / Rapid / 6.0-6.0
    dizziness / Early / 6.0-6.0
    nausea / Early / 6.0-6.0
    diarrhea / Early / 6.0-6.0
    arthralgia / Early / 6.0-6.0
    malaise / Early / 6.0-6.0
    weight loss / Delayed / 6.0-6.0
    syncope / Early / Incidence not known
    tremor / Early / Incidence not known

    DRUG INTERACTIONS

    Acetaminophen; Aspirin, ASA; Caffeine: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Acetaminophen; Caffeine; Magnesium Salicylate; Phenyltoloxamine: (Moderate) Use dichlorphenamide and magnesium salicylate together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Acetazolamide: (Major) Use dichlorphenamide and acetazolamide, another carbonic anhydrase inhibitor, together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Aclidinium; Formoterol: (Moderate) Use dichlorphenamide and arformoterol or formoterol together with caution. Metabolic acidosis is listed by the manufacturers of arformoterol and formoterol as an adverse reaction seen with beta-2 agonists but would be rare with normal doses of arformoterol or formoterol. Metabolic acidosis has been reported with dichlorphenamide. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Adefovir: (Major) Use of dichlorphenamide and adefovir is not recommended because of increased adefovir exposure and a risk of adefovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal function for all patients during treatment with adefovir, as the drug may cause nephrotoxicity. Increased adefovir exposure is possible. Adefovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Albuterol: (Moderate) Use dichlorphenamide and albuterol together with caution. Metabolic acidosis has been reported with dichlorphenamide and albuterol aerosol and inhalation solution. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Aldesleukin, IL-2: (Moderate) Use dichlorphenamide and aldesleukin, IL-2 together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Allopurinol: (Moderate) Use dichlorphenamide and allopurinol together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Alogliptin; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Aluminum Hydroxide; Magnesium Hydroxide: (Moderate) Use dichlorphenamide and magnesium hydroxide together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Aluminum Hydroxide; Magnesium Hydroxide; Simethicone: (Moderate) Use dichlorphenamide and magnesium hydroxide together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Amiloride: (Moderate) Use dichlorphenamide and amiloride together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amiloride; Hydrochlorothiazide, HCTZ: (Moderate) Use dichlorphenamide and amiloride together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ammonium Chloride: (Moderate) Use dichlorphenamide and ammonium chloride together with caution. Metabolic acidosis secondary to hyperchloremia can occur in patients who are given large doses of ammonium chloride and is especially likely in patients with impaired renal function. Dichlorphenamide is also associated with metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amoxicillin: (Moderate) Use dichlorphenamide and amoxicillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including amoxicillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amoxicillin; Clarithromycin; Omeprazole: (Moderate) Use dichlorphenamide and amoxicillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including amoxicillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amoxicillin; Clavulanic Acid: (Moderate) Use dichlorphenamide and amoxicillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including amoxicillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amphotericin B cholesteryl sulfate complex (ABCD): (Moderate) Use dichlorphenamide and antifungals together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. In addition, both dichlorphenamide and some amphotericin B products (i.e., amphotericin B cholesteryl sulfate complex (ABCD), amphotericin B lipid complex (ABLC), amphotericin B liposomal (LAmB)) can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amphotericin B lipid complex (ABLC): (Moderate) Use dichlorphenamide and antifungals together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. In addition, both dichlorphenamide and some amphotericin B products (i.e., amphotericin B cholesteryl sulfate complex (ABCD), amphotericin B lipid complex (ABLC), amphotericin B liposomal (LAmB)) can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amphotericin B liposomal (LAmB): (Moderate) Use dichlorphenamide and antifungals together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. In addition, both dichlorphenamide and some amphotericin B products (i.e., amphotericin B cholesteryl sulfate complex (ABCD), amphotericin B lipid complex (ABLC), amphotericin B liposomal (LAmB)) can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Amphotericin B: (Moderate) Use dichlorphenamide and antifungals together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. In addition, both dichlorphenamide and some amphotericin B products (i.e., amphotericin B cholesteryl sulfate complex (ABCD), amphotericin B lipid complex (ABLC), amphotericin B liposomal (LAmB)) can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ampicillin: (Moderate) Use dichlorphenamide and ampicillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including ampicillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ampicillin; Sulbactam: (Moderate) Use dichlorphenamide and ampicillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including ampicillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Anidulafungin: (Moderate) Use dichlorphenamide and antifungals together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Arformoterol: (Moderate) Use dichlorphenamide and arformoterol or formoterol together with caution. Metabolic acidosis is listed by the manufacturers of arformoterol and formoterol as an adverse reaction seen with beta-2 agonists but would be rare with normal doses of arformoterol or formoterol. Metabolic acidosis has been reported with dichlorphenamide. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Articaine; Epinephrine: (Moderate) Use dichlorphenamide and epinephrine together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the long-term use epinephrine. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Aspirin, ASA: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Butalbital; Caffeine: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Butalbital; Caffeine; Codeine: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Caffeine: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Caffeine; Dihydrocodeine: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Caffeine; Orphenadrine: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Carisoprodol: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Carisoprodol; Codeine: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Citric Acid; Sodium Bicarbonate: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Dipyridamole: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Omeprazole: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Oxycodone: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Aspirin, ASA; Pravastatin: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
    Basiliximab: (Moderate) Use dichlorphenamide and basiliximab together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Major) Use of dichlorphenamide and tenofovir alafenamide is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Bisacodyl: (Moderate) Use dichlorphenamide and bisacodyl together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Budesonide; Formoterol: (Moderate) Use dichlorphenamide and arformoterol or formoterol together with caution. Metabolic acidosis is listed by the manufacturers of arformoterol and formoterol as an adverse reaction seen with beta-2 agonists but would be rare with normal doses of arformoterol or formoterol. Metabolic acidosis has been reported with dichlorphenamide. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Budesonide; Glycopyrrolate; Formoterol: (Moderate) Use dichlorphenamide and arformoterol or formoterol together with caution. Metabolic acidosis is listed by the manufacturers of arformoterol and formoterol as an adverse reaction seen with beta-2 agonists but would be rare with normal doses of arformoterol or formoterol. Metabolic acidosis has been reported with dichlorphenamide. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Bumetanide: (Moderate) Use dichlorphenamide and bumetanide together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including bumetanide. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Bupivacaine; Epinephrine: (Moderate) Use dichlorphenamide and epinephrine together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the long-term use epinephrine. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Calcium Carbonate; Famotidine; Magnesium Hydroxide: (Major) Concomitant use of dichlorphenamide and famotidine is not recommended because of an increased risk of famotidine-related adverse effects. Monitor closely for signs of famotidine-related drug toxicity if coadministration cannot be avoided. Increased famotidine exposure is possible. Dichlorphenamide inhibits OAT1. Famotidine is a sensitive OAT1 substrate. Consider if an alternative to famotidine would be appropriate for the patient.
    Canagliflozin; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Casanthranol; Docusate Sodium: (Moderate) Use dichlorphenamide and docusate together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Caspofungin: (Moderate) Use dichlorphenamide and caspofungin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Castor Oil: (Moderate) Use dichlorphenamide and castor oil together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Cefaclor: (Moderate) Use of dichlorphenamide and cefaclor is not recommended because of an increased risk of cefaclor-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. Increased cefaclor exposure is possible. Dichlorphenamide inhibits OAT1. Cefaclor is an OAT1 substrate.
    Ceftizoxime: (Moderate) Use of dichlorphenamide and ceftizoxime is not recommended because of an increased risk of ceftizoxime-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. Increased ceftizoxime exposure is possible. Dichlorphenamide inhibits OAT1. Ceftizoxime is an OAT1 substrate.
    Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) Use dichlorphenamide and ibuprofen together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Choline Salicylate; Magnesium Salicylate: (Moderate) Use dichlorphenamide and magnesium salicylate together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Cidofovir: (Major) Use of dichlorphenamide and adefovir is not recommended because of increased cidofovir exposure and related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal function and for neutropenia for all patients during treatment with cidofovir. Increased cidofovir exposure is possible. Cidofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1. Concurrent use may also increase the severity of metabolic acidosis, as both drugs may cause this side effect. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Cyclosporine: (Moderate) Use dichlorphenamide and systemic cyclosporine together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Dapagliflozin; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Major) Use of dichlorphenamide and tenofovir alafenamide is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Decitabine: (Moderate) Use dichlorphenamide and decitabine together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Decitabine; Cedazuridine: (Moderate) Use dichlorphenamide and decitabine together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Deferiprone: (Moderate) Use dichlorphenamide and deferiprone together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the postmarketing use of deferiprone. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Desflurane: (Moderate) Use dichlorphenamide and desflurane together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the postmarketing use of desflurane. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Dicloxacillin: (Moderate) Use dichlorphenamide and dicloxacillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including dicloxacillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Diphenhydramine; Ibuprofen: (Moderate) Use dichlorphenamide and ibuprofen together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Docusate Sodium; Senna: (Moderate) Use dichlorphenamide and docusate together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Docusate: (Moderate) Use dichlorphenamide and docusate together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Efavirenz; Emtricitabine; Tenofovir: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Major) Use of dichlorphenamide and tenofovir alafenamide is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Empagliflozin; Linagliptin; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Empagliflozin; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Major) Use of dichlorphenamide and tenofovir alafenamide is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Emtricitabine; Tenofovir alafenamide: (Major) Use of dichlorphenamide and tenofovir alafenamide is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Emtricitabine; Tenofovir disoproxil fumarate: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Epinephrine: (Moderate) Use dichlorphenamide and epinephrine together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the long-term use epinephrine. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ertugliflozin; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Ethacrynic Acid: (Moderate) Use dichlorphenamide and ethacrynic acid together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including ethacrynic acid. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Etoposide, VP-16: (Moderate) Use dichlorphenamide and etoposide, VP-16 together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported in patients who received higher doses of single agent etoposide given orally or as an IV injection. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ezogabine: (Moderate) Monitor for increased toxicity of dichlorphenamide, including hypokalemia and hyperchloremic metabolic acidosis, if ezogabine and dichlorphenamide are coadministered. Dichlorphenamide is a substrate for OAT3. Ezogabine may increase exposure to dichlorphenamide through OAT3 inhibition. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Famotidine: (Major) Concomitant use of dichlorphenamide and famotidine is not recommended because of an increased risk of famotidine-related adverse effects. Monitor closely for signs of famotidine-related drug toxicity if coadministration cannot be avoided. Increased famotidine exposure is possible. Dichlorphenamide inhibits OAT1. Famotidine is a sensitive OAT1 substrate. Consider if an alternative to famotidine would be appropriate for the patient.
    Famotidine; Ibuprofen: (Major) Concomitant use of dichlorphenamide and famotidine is not recommended because of an increased risk of famotidine-related adverse effects. Monitor closely for signs of famotidine-related drug toxicity if coadministration cannot be avoided. Increased famotidine exposure is possible. Dichlorphenamide inhibits OAT1. Famotidine is a sensitive OAT1 substrate. Consider if an alternative to famotidine would be appropriate for the patient. (Moderate) Use dichlorphenamide and ibuprofen together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Fidaxomicin: (Moderate) Use dichlorphenamide and fidaxomicin together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Fluconazole: (Moderate) Use dichlorphenamide and fluconazole together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Flucytosine: (Moderate) Use dichlorphenamide and flucytosine together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Formoterol: (Moderate) Use dichlorphenamide and arformoterol or formoterol together with caution. Metabolic acidosis is listed by the manufacturers of arformoterol and formoterol as an adverse reaction seen with beta-2 agonists but would be rare with normal doses of arformoterol or formoterol. Metabolic acidosis has been reported with dichlorphenamide. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Formoterol; Mometasone: (Moderate) Use dichlorphenamide and arformoterol or formoterol together with caution. Metabolic acidosis is listed by the manufacturers of arformoterol and formoterol as an adverse reaction seen with beta-2 agonists but would be rare with normal doses of arformoterol or formoterol. Metabolic acidosis has been reported with dichlorphenamide. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Furosemide: (Moderate) Concomitant use of dichlorphenamide and furosemide is not recommended because of an increased risk of furosemide-related adverse effects and risk for hypokalemia. Monitor closely for signs of drug toxicity if coadministration cannot be avoided in some patients furosemide dose adjustment might be necessary. Increased furosemide exposure is possible. Dichlorphenamide inhibits OAT1. Furosemide is an OAT1 substrate. Dichlorphenamide also increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including furosemide. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Gallium Ga 68 Dotatate: (Moderate) Use dichlorphenamide and mannitol together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ganciclovir: (Major) Use of dichlorphenamide and ganciclovir is not recommended because of an increased risk of ganciclovir-related adverse effects. Monitor closely for signs of drug toxicity if use together cannot be avoided. For example, the main toxicities of ganciclovir are myelosuppresion or nephrotoxicity. Monitor blood counts and renal function, since increased ganciclovir exposure is possible. Dichlorphenamide inhibits OAT1. Ganciclovir is an OAT1 substrate. Additionally, metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the postmarketing use of ganciclovir. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Glipizide; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Glyburide; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Glycopyrrolate; Formoterol: (Moderate) Use dichlorphenamide and arformoterol or formoterol together with caution. Metabolic acidosis is listed by the manufacturers of arformoterol and formoterol as an adverse reaction seen with beta-2 agonists but would be rare with normal doses of arformoterol or formoterol. Metabolic acidosis has been reported with dichlorphenamide. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Griseofulvin: (Moderate) Use dichlorphenamide and griseofulvin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Hetastarch: (Moderate) Use dichlorphenamide and hetastarch together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Hetastarch; Dextrose; Electrolytes: (Moderate) Use dichlorphenamide and hetastarch together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Hydrocodone; Ibuprofen: (Moderate) Use dichlorphenamide and ibuprofen together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Ibritumomab Tiuxetan: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Ibuprofen: (Moderate) Use dichlorphenamide and ibuprofen together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ibuprofen; Oxycodone: (Moderate) Use dichlorphenamide and ibuprofen together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ibuprofen; Pseudoephedrine: (Moderate) Use dichlorphenamide and ibuprofen together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ipratropium; Albuterol: (Moderate) Use dichlorphenamide and albuterol together with caution. Metabolic acidosis has been reported with dichlorphenamide and albuterol aerosol and inhalation solution. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Isavuconazonium: (Moderate) Use dichlorphenamide and isavuconazonium together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Isoniazid, INH: (Moderate) Use dichlorphenamide and isoniazid, INH together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Moderate) Use dichlorphenamide and isoniazid, INH together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Isoniazid, INH; Rifampin: (Moderate) Use dichlorphenamide and isoniazid, INH together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Itraconazole: (Moderate) Use dichlorphenamide and itraconazole together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Ixabepilone: (Moderate) Use dichlorphenamide and ixabepilone together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Ketoconazole: (Moderate) Use dichlorphenamide and ketoconazole together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Lactulose: (Moderate) Use dichlorphenamide and lactulose together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and could occur with lactulose in the presence of persistent and severe diarrhea. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Lansoprazole; Amoxicillin; Clarithromycin: (Moderate) Use dichlorphenamide and amoxicillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including amoxicillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Leflunomide: (Moderate) Monitor for increased toxicity of dichlorphenamide, including hypokalemia and hyperchloremic metabolic acidosis, if leflunomide and dichlorphenamide are coadministered. Dichlorphenamide is a substrate for OAT3. Teriflunomide, the active metabolite of leflunomide, may increase exposure to dichlorphenamide through OAT3 inhibition. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Lesinurad; Allopurinol: (Moderate) Use dichlorphenamide and allopurinol together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Levalbuterol: (Moderate) Use dichlorphenamide and albuterol together with caution. Metabolic acidosis has been reported with dichlorphenamide and albuterol aerosol and inhalation solution. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Levoketoconazole: (Moderate) Use dichlorphenamide and ketoconazole together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Lidocaine; Epinephrine: (Moderate) Use dichlorphenamide and epinephrine together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the long-term use epinephrine. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Linagliptin; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Lorazepam: (Moderate) Use dichlorphenamide and lorazepam together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported rarely with the use of lorazepam injection for the treatment of status epilepticus. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Lubiprostone: (Moderate) Use dichlorphenamide and lubiprostone together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Magnesium Citrate: (Moderate) Use dichlorphenamide and magnesium citrate together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Magnesium Hydroxide: (Moderate) Use dichlorphenamide and magnesium hydroxide together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Magnesium Salicylate: (Moderate) Use dichlorphenamide and magnesium salicylate together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Magnesium Sulfate; Potassium Sulfate; Sodium Sulfate: (Moderate) Use dichlorphenamide and magnesium sulfate; potassium sulfate; sodium sulfate together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Mannitol: (Moderate) Use dichlorphenamide and mannitol together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Metformin; Repaglinide: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Metformin; Rosiglitazone: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Metformin; Saxagliptin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Metformin; Sitagliptin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Methazolamide: (Major) Use dichlorphenamide and methazolamide, another carbonic anhydrase inhibitor, together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Methenamine; Sodium Acid Phosphate: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Methotrexate: (Major) Concomitant use of dichlorphenamide and methotrexate is not recommended because of an increased risk of methotrexate-related adverse effects. This combination should be avoided, since increased methotrexate exposure may cause severe toxicity. Monitor closely for signs of methotrexate toxicity if coadministration cannot be avoided, including signs and symptoms of bone marrow toxicity/ immunosuppression (sore throat, fever, reduced blood counts, unusual bruising or bleeding) and liver toxicity, as examples. Increased methotrexate exposure is possible. Methotrexate is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Methylcellulose: (Moderate) Use dichlorphenamide and methylcellulose together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Micafungin: (Moderate) Use dichlorphenamide and antifungals together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Mineral Oil: (Moderate) Use dichlorphenamide and mineral oil together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Mycophenolate: (Moderate) Use dichlorphenamide and mycophenolate together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Nafcillin: (Moderate) Use dichlorphenamide and nafcillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including nafcillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Nelfinavir: (Moderate) Use dichlorphenamide and nelfinavir together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the postmarketing use of nelfinavir. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Netupitant, Fosnetupitant; Palonosetron: (Moderate) Use dichlorphenamide and palonosetron together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Omeprazole; Amoxicillin; Rifabutin: (Moderate) Use dichlorphenamide and amoxicillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including amoxicillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Oseltamivir: (Major) Concomitant use of dichlorphenamide and oseltamivir is not recommended because of an increased risk of oseltamivir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. Increased oseltamivir exposure is possible. Dichlorphenamide inhibits OAT1. Oseltamivir is a sensitive OAT1 substrate. Consider if an alternative to oseltamivir would be appropriate for the patient.
    Oxacillin: (Moderate) Use dichlorphenamide and oxacillin together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including oxacillin. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Palonosetron: (Moderate) Use dichlorphenamide and palonosetron together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Penicillin G Benzathine: (Moderate) Use of dichlorphenamide and with OAT1 substrates like penicillin G is not recommended because of increased penicillin G exposure. If use cannot be avoided, monitor for increased adverse effects due to increased penicillin G exposure. Dichlorphenamide inhibits OAT1. Dichlorphenamide also increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including penicillin G. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Penicillin G Benzathine; Penicillin G Procaine: (Moderate) Use of dichlorphenamide and with OAT1 substrates like penicillin G is not recommended because of increased penicillin G exposure. If use cannot be avoided, monitor for increased adverse effects due to increased penicillin G exposure. Dichlorphenamide inhibits OAT1. Dichlorphenamide also increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including penicillin G. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Penicillin G Procaine: (Moderate) Use of dichlorphenamide and with OAT1 substrates like penicillin G is not recommended because of increased penicillin G exposure. If use cannot be avoided, monitor for increased adverse effects due to increased penicillin G exposure. Dichlorphenamide inhibits OAT1. Dichlorphenamide also increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including penicillin G. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Penicillin G: (Moderate) Use of dichlorphenamide and with OAT1 substrates like penicillin G is not recommended because of increased penicillin G exposure. If use cannot be avoided, monitor for increased adverse effects due to increased penicillin G exposure. Dichlorphenamide inhibits OAT1. Dichlorphenamide also increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including penicillin G. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Penicillin V: (Moderate) Use dichlorphenamide and penicillin V together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including penicillin V. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Phentermine; Topiramate: (Moderate) Use dichlorphenamide and topiramate, another carbonic anhydrase inhibitor, together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Pioglitazone; Metformin: (Moderate) Carbonic anhydrase inhibitors such as dichlorphenamide frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of dichlorphenamide with metformin may increase the risk for lactic acidosis; consider more frequent monitoring. Carbonic anhydrase inhibitors may also alter blood sugar; both hyperglycemia and hypoglycemia have been described. Monitor blood glucose and for changes in glycemic control and be alert for evidence of an interaction.
    Polyethylene Glycol: (Moderate) Use dichlorphenamide and polyethylene glycol; electrolytes together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Polyethylene Glycol; Electrolytes: (Moderate) Use dichlorphenamide and magnesium sulfate; potassium sulfate; sodium sulfate together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy. (Moderate) Use dichlorphenamide and polyethylene glycol; electrolytes together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Polyethylene Glycol; Electrolytes; Ascorbic Acid: (Moderate) Use dichlorphenamide and magnesium sulfate; potassium sulfate; sodium sulfate together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy. (Moderate) Use dichlorphenamide and polyethylene glycol; electrolytes together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Polyethylene Glycol; Electrolytes; Bisacodyl: (Moderate) Use dichlorphenamide and bisacodyl together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy. (Moderate) Use dichlorphenamide and polyethylene glycol; electrolytes together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Posaconazole: (Moderate) Use dichlorphenamide and antifungals together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Potassium Phosphate; Sodium Phosphate: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Prilocaine; Epinephrine: (Moderate) Use dichlorphenamide and epinephrine together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the long-term use epinephrine. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Probenecid: (Moderate) Monitor for increased toxicity of dichlorphenamide, including hypokalemia and hyperchloremic metabolic acidosis, if probenecid and dichlorphenamide are coadministered. Dichlorphenamide is a substrate for OAT1 and OAT3. Probenecid may increase exposure to dichlorphenamide through OAT1 and OAT3 inhibition. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Probenecid; Colchicine: (Moderate) Monitor for increased toxicity of dichlorphenamide, including hypokalemia and hyperchloremic metabolic acidosis, if probenecid and dichlorphenamide are coadministered. Dichlorphenamide is a substrate for OAT1 and OAT3. Probenecid may increase exposure to dichlorphenamide through OAT1 and OAT3 inhibition. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Propofol: (Moderate) Use dichlorphenamide and propofol together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Psyllium: (Moderate) Use dichlorphenamide and psyllium together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Pyridoxine, Vitamin B6: (Moderate) Use dichlorphenamide and pyridoxine, vitamin B6 together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with the rapid infusion of large pyridoxine doses. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Salsalate: (Moderate) Use dichlorphenamide and salsalate together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Senna: (Minor) Use dichlorphenamide and senna together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Senna very rarely causes hypokalemia. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Sevelamer: (Moderate) Use dichlorphenamide and sevelamer together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Sodium benzoate; sodium phenylacetate: (Moderate) Use dichlorphenamide and sodium benzoate; sodium phenylacetate together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Sodium Phenylbutyrate: (Moderate) Use dichlorphenamide and sodium phenylbutyrate together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with phenylbutyrate in patients with urea cycle disorders. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Moderate) Use dichlorphenamide and sodium picosulfate; magnesium oxide; anhydrous citric acid together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Sorbitol: (Moderate) Use dichlorphenamide and sorbitol together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with large volumes of sorbitol irrigation where systemic absorption occurs. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Spironolactone: (Moderate) Use dichlorphenamide and spironolactone together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with spironolactone in patients with decompensated hepatic cirrhosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Spironolactone; Hydrochlorothiazide, HCTZ: (Moderate) Use dichlorphenamide and spironolactone together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with spironolactone in patients with decompensated hepatic cirrhosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Teniposide: (Moderate) Use dichlorphenamide and teniposide together with caution. Metabolic acidosis is associated with the use of dichlorphenamide and has been reported with teniposide in patients who received higher than recommended doses. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Tenofovir Alafenamide: (Major) Use of dichlorphenamide and tenofovir alafenamide is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Tenofovir Alafenamide: (Major) Use of dichlorphenamide and tenofovir alafenamide is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Tenofovir, PMPA: (Major) Use of dichlorphenamide and tenofovir disoproxil fumarate is not recommended because of increased tenofovir exposure and a risk of tenofovir-related adverse effects. Monitor closely for signs of drug toxicity if coadministration cannot be avoided. For example, it is important to monitor renal and hepatic function for all patients during treatment with tenofovir, as the drug may cause hepatotoxicity or nephrotoxicity. Increased tenofovir exposure is possible. Tenofovir is a sensitive OAT1 substrate. Dichlorphenamide inhibits OAT1.
    Terbinafine: (Moderate) Use dichlorphenamide and terbinafine together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Teriflunomide: (Moderate) Monitor for increased toxicity of dichlorphenamide, including hypokalemia and hyperchloremic metabolic acidosis, if teriflunomide and dichlorphenamide are coadministered. Dichlorphenamide is a substrate for OAT3. Teriflunomide may increase exposure to dichlorphenamide through OAT3 inhibition. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Theophylline, Aminophylline: (Moderate) Use dichlorphenamide and theophylline, aminophylline together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including theophylline, aminophylline. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Thiazide diuretics: (Moderate) Use dichlorphenamide and diuretics together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including loop diuretics and thiazide diuretics. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Tigecycline: (Moderate) Use dichlorphenamide and tigecycline together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Topiramate: (Moderate) Use dichlorphenamide and topiramate, another carbonic anhydrase inhibitor, together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Torsemide: (Moderate) Use dichlorphenamide and torsemide together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including torsemide. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Triamterene: (Moderate) Use dichlorphenamide and triamterene together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Triamterene; Hydrochlorothiazide, HCTZ: (Moderate) Use dichlorphenamide and triamterene together with caution as both drugs can cause metabolic acidosis. Concurrent use may increase the severity of metabolic acidosis. Measure sodium bicarbonate concentrations at baseline and periodically during dichlorphenamide treatment. If metabolic acidosis occurs or persists, consider reducing the dose or discontinuing dichlorphenamide therapy.
    Vincristine Liposomal: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Voriconazole: (Moderate) Use dichlorphenamide and voriconazole together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including antifungals. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Zonisamide: (Moderate) Monitor for the appearance or worsening of metabolic acidosis if zonisamide is given concomitantly with dichlorphenamide. Concomitant use of zonisamide with another carbonic anhydrase inhibitor, like dichlorphenamide, may increase the severity of metabolic acidosis and may also increase the risks of hyperammonemia, encephalopathy, and kidney stone formation. Monitor serum ammonia concentrations if signs or symptoms of encephalopathy occur. Hyperammonemia resulting from zonisamide resolves when zonisamide is discontinued and may resolve or decrease in severity with a decrease of the daily dose. If metabolic acidosis develops, consider reducing the dose or discontinuing dichlorphenamide.

    PREGNANCY AND LACTATION

    Pregnancy

    There are no data on the presence of dichlorphenamide in human milk, the effects on the breastfed infant, or the effects on milk production. Consider the developmental and health benefits of breast-feeding along with the mother's clinical need for dichlorphenamide and any potential adverse effects on the breast-fed infant from dichlorphenamide or the underlying maternal condition.

    MECHANISM OF ACTION

    Dichlorphenamide is a carbonic anhydrase inhibitor. It is unknown how dichlorphenamide exerts its therapeutic effects in patients with periodic paralysis.

    PHARMACOKINETICS

    Dichlorphenamide is administered orally. The plasma protein binding of dichlorphenamide is approximately 88%. Dichlorphenamide is a substrate for transporters OAT1 and OAT3. The mean terminal half-life was in the range of 32 to 66 hours following single dose administration.
     
    Affected cytochrome P450 (CYP450) isoenzymes and drug transporters: OAT1, OAT3
    Dichlorphenamide is an inhibitor of OAT1. Dichlorphenamide is a substrate for transporters OAT1 and OAT3. Dichlorphenamide is not an inhibitor for CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A4 enzymes when tested in vitro. Dichlorphenamide is not an inducer for CYP1A2, 2B6, or 3A4 enzymes when tested in vitro. Dichlorphenamide is neither a substrate nor inhibitor for p-gp, BCRP, OATP1B1, OATP1B3, OAT2, OAT4, OCT1, OCT2, MATE1, or MATE2-K when tested in vitro.

    Oral Route

    Dichlorphenamide Cmax and AUC (exposure) increased in a dose-proportional manner within the range of 25 mg to 400 mg following single-dose administration in healthy subjects in a fasted state. Steady-state is expected to be achieved within 10 days of oral dosing. The time to maximum concentration (Tmax) of dichlorphenamide was approximately 1.5 to 3 hours after single and multiple dose administrations, respectively.