CLASSES

Varicella Zoster Antitoxins and Immunoglobulins

DEA CLASS

Rx

DESCRIPTION

Purified human immune globulin G (IgG) containing antibodies to varicella-zoster virus (anti-VZV)
For post-exposure prophylaxis of varicella in high risk individuals
Product may be obtained by contacting FFF Enterprises at 1-800-843-7477 or ASD Healthcare at 1-800-746-6273

COMMON BRAND NAMES

VARIZIG, VARIZIG Powder

HOW SUPPLIED

Varicella Zoster Immune Globulin (Human)/VARIZIG Intramuscular Inj Sol: 125IU
VARIZIG Powder Intramuscular Inj Pwd F/Sol: 125IU

DOSAGE & INDICATIONS

MAXIMUM DOSAGE

625 International units/dose IM.

625 International units/dose IM.

40.1 kg and more: 625 International units/dose IM.
30.1 to 40 kg: 500 International units/dose IM.
20.1 to 30 kg: 375 International units/dose IM.

40.1 kg and more: 625 International units/dose IM.
30.1 to 40 kg: 500 International units/dose IM.
20.1 to 30 kg: 375 International units/dose IM.
10.1 to 20 kg: 250 International units/dose IM.
2.1 to 10 kg: 125 International units/dose IM.

10.1 to 20 kg: 250 International units/dose IM.
2.1 to 10 kg: 125 International units/dose IM.

2.1 to 10 kg: 125 International units/dose IM.
2 kg and less: 62.5 International units/dose IM.

DOSING CONSIDERATIONS

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

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

ADMINISTRATION

Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit. Do not use if the solution is cloudy or contains particulates.[52697]

STORAGE

VARIZIG:
- Discard product if it contains particulate matter, is cloudy, or discolored
- Discard unused portion. Do not store for later use.
- Do not freeze
- Store between 36 to 46 degrees F
- Store in a cool, well ventilated, dry place
- Store in original container
VARIZIG Powder:
- Discard unused portion. Do not store for later use.
- Do not freeze
- Store between 36 to 46 degrees F
- Use within 12 hours after reconstitution

CONTRAINDICATIONS / PRECAUTIONS

Varicella-zoster immune globulin is contraindicated for use by patients known to have anaphylactic or severe systemic reactions to human immune globulin preparations. Varicella-zoster immune globulin is also contraindicated for use by IgA-deficient patients with antibodies against IgA and a history of hypersensitivity, as they may have an anaphylactoid reaction. Patients with IgA deficiency often develop antibodies against IgA and are more likely to have anaphylactic or immune-mediated adverse reactions to pooled immunoglobulin products. Varicella-zoster immune globulin contains less than 40 mcg/mL of IgA.

As with other products derived from or purified with human blood components, the possibility of transmission of infectious agents such as the variant Creutzfeldt-Jakob disease agent and, theoretically, the Creutzfeldt-Jakob disease agent exists in patients receiving varicella-zoster immune globulin. Screening plasma donors for prior exposure to certain viruses, testing for the presence of viruses, and inactivating or reducing viruses has reduced the risk of infection transmission from varicella-zoster immune globulin. The manufacturing processes are designed to reduce the risk of transmitting viral infection; however, none of the processes are completely effective. There is also the possibility that unknown infectious agents may be present in this product. Discuss the risks and benefits of this product with the patient before administration.

Only administer varicella-zoster immune globulin to patients who have severe thrombocytopenia or any coagulopathy like hemophilia that would contraindicate intramuscular injections if the expected benefits outweigh the potential risks.

Varicella-zoster immune globulin is indicated for post-exposure prophylaxis in high-risk patients such as pregnant women. The manufacturer recommends use during pregnancy only when clearly needed; FDA pregnancy category C drug. According to the recommendations of the Advisory Committee on Immunization Practices, strongly consider varicella zoster immune globulin for pregnant women without evidence of immunity who have been exposed because pregnant women might be at higher risk for severe varicella and complications. Administration of varicella-zoster immune globulin to these women has not been found to prevent viremia, fetal infection, congenital varicella syndrome, or neonatal varicella. Thus, the primary indication for varicella-zoster immune globulin in pregnant women is to prevent complications of varicella in the mother rather than to protect the fetus.

No data are available from the manufacturer regarding the use of varicella-zoster immune globulin during breast-feeding; excretion into breast milk is unknown.[52697] Case reports of 2 nursing mothers receiving intravenous immune globulin therapy suggest transfer of IgG and IgM into the colostrum and breast milk. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, health care providers are encouraged to report the adverse effect to the FDA.[48199]

The immune globulins present in varicella-zoster immune globulin may impair the efficacy of live virus vaccination such as varicella vaccine, measles, mumps, and rubella (MMR) vaccine, and the measles, mumps, rubella, and varicella vaccine. Antibodies in immune globulin products may interfere with patient responses to live vaccines because the continued presence of high concentrations of passively acquired antibody may interfere with an active antibody response. According to the manufacturer, delay live virus vaccinations until approximately 3 months after varicella-zoster immune globulin administration. However, guidelines recommend waiting at least 5 months after receipt of the varicella-zoster immune globulin before administering either the measle or varicella vaccines. Conversely, if either measles or varicella vaccines are given, 2 weeks are recommended to elapse before varicella-zoster immune globulin administration. The yellow fever vaccine, rotavirus vaccine, oral Ty21a typhoid vaccine, live attenuated influenza vaccine, and the zoster vaccine may be administered at any time in relation to receipt of an antibody-containing product. Inform the immunizing physician about recent therapy with immune globulin products prior to vaccination.

Thrombotic events may occur during or after treatment with immune globulin products. Cautious use of varicella-zoster immune globulin is warranted in patients with a history of cardiac disease or thromboembolic disease. Patients at risk for thrombotic events are geriatric patients, those with a history of atherosclerosis (coronary artery disease), multiple cardiovascular risk factors, impaired cardiac output (heart failure), coagulation disorders, prolonged periods of immobilization, obesity, diabetes mellitus, acquired or inherited thrombophilic disorder, a history of vascular disease, a history of a previous thrombotic or thromboembolic event, and/or known or suspected hyperviscosity. Assessment of baseline blood viscosity may be warranted for patients at risk for hyperviscosity such as those with cryoglobulins, fasting chylomicronemia, hypertriglyceridemia, or monoclonal gammopathies.

ADVERSE REACTIONS

serum sickness / Delayed / 0-1.0
coagulopathy / Delayed / 0-1.0
intracranial bleeding / Delayed / 0-1.0
disseminated intravascular coagulation (DIC) / Delayed / 0-1.0
thrombosis / Delayed / 0-1.0
intraventricular hemorrhage / Delayed / 0-1.0
anaphylactic shock / Rapid / Incidence not known

injection site reaction / Rapid / 3.0-3.0
headache / Early / 2.0-2.0
pruritus / Rapid / 0-1.0
fatigue / Early / 1.0-1.0
vesicular rash / Delayed / 0-1.0
urticaria / Rapid / 0-1.0
chills / Rapid / 1.0-1.0
rash / Early / 1.0-1.0
nausea / Early / 1.0-1.0
infection / Delayed / Incidence not known

DRUG INTERACTIONS

Measles Virus; Mumps Virus; Rubella Virus; Varicella Virus Vaccine, Live: (Major) Efficacy of live attenuated virus vaccines such as measles/mumps/rubella Vaccines, MMR; rotavirus vaccine; and varicella virus vaccine live may be impaired by varicella-zoster immune globulin administration; revaccination may be necessary. As the passive transfer of antibodies may impair the efficacy of live attenuated virus vaccines, defer vaccination with live virus vaccines until approximately 3 months after varicella-zoster immune globulin administration. Inform the immunizing physician of recent therapy with varicella-zoster immune globulin, so that appropriate measures can be taken.
Measles/Mumps/Rubella Vaccines, MMR: (Major) Efficacy of live attenuated virus vaccines such as measles/mumps/rubella Vaccines, MMR; rotavirus vaccine; and varicella virus vaccine live may be impaired by varicella-zoster immune globulin administration; revaccination may be necessary. As the passive transfer of antibodies may impair the efficacy of live attenuated virus vaccines, defer vaccination with live virus vaccines until approximately 3 months after varicella-zoster immune globulin administration. Inform the immunizing physician of recent therapy with varicella-zoster immune globulin, so that appropriate measures can be taken.
Rotavirus Vaccine: (Major) Defer vaccination with live virus vaccines until approximately 3 months after Varicella Zoster immune globulin administration. Inform the immunizing physician of recent therapy with varicella-zoster immune globulin, so that appropriate measures can be taken. The efficacy of live attenuated virus vaccines such as Rotavirus Vaccine may be impaired by Varicella Zoster immune globulin administration; revaccination may be necessary. The passive transfer of antibodies from the immune globulin may impair the efficacy of live attenuated virus vaccines.
Rubella Virus Vaccine Live: (Major) Efficacy of live attenuated virus vaccines such as measles/mumps/rubella Vaccines, MMR; rotavirus vaccine; and varicella virus vaccine live may be impaired by varicella-zoster immune globulin administration; revaccination may be necessary. As the passive transfer of antibodies may impair the efficacy of live attenuated virus vaccines, defer vaccination with live virus vaccines until approximately 3 months after varicella-zoster immune globulin administration. Inform the immunizing physician of recent therapy with varicella-zoster immune globulin, so that appropriate measures can be taken.

PREGNANCY AND LACTATION

Varicella-zoster immune globulin is indicated for post-exposure prophylaxis in high-risk patients such as pregnant women. The manufacturer recommends use during pregnancy only when clearly needed; FDA pregnancy category C drug. According to the recommendations of the Advisory Committee on Immunization Practices, strongly consider varicella zoster immune globulin for pregnant women without evidence of immunity who have been exposed because pregnant women might be at higher risk for severe varicella and complications. Administration of varicella-zoster immune globulin to these women has not been found to prevent viremia, fetal infection, congenital varicella syndrome, or neonatal varicella. Thus, the primary indication for varicella-zoster immune globulin in pregnant women is to prevent complications of varicella in the mother rather than to protect the fetus.

No data are available from the manufacturer regarding the use of varicella-zoster immune globulin during breast-feeding; excretion into breast milk is unknown.[52697] Case reports of 2 nursing mothers receiving intravenous immune globulin therapy suggest transfer of IgG and IgM into the colostrum and breast milk. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, health care providers are encouraged to report the adverse effect to the FDA.[48199]

MECHANISM OF ACTION

Varicella-zoster immune globulin is a preparation of purified human immune globulin G (IgG) containing antibodies to varicella-zoster virus (anti-VZV) and, thus, provides passive immunization for non-immune individuals exposed to the varicella-zoster virus. The product may reduce the severity of varicella infections. No convincing evidence exists that the product reduces the incidence of chickenpox infection after exposure to the virus or that established varicella infections can be modified with the product. Of note, varicella-zoster immune globulin might extend the incubation period of the virus from 10 to 21 days to 28 days or more.

PHARMACOKINETICS

Varicella-zoster immune globulin is administered via intramuscular (IM) injection. Antibody protection against the varicella zoster virus generally lasts for 3 weeks after product administration in both children and adults. The exact fate of human immunoglobulin products is not well defined, but the mean serum half-life is 26.2 +/- 4.6 days after receipt of 12.5 International units/kg IM.[52697]