Dosing and uses of VariZIG (varicella zoster immune globulin, human)
Adult dosage forms and strengths
intramuscular injection
- 125 IU/vial (lyophilized powder)
- 100 IU/mL (after reconstitution)
Varicella, Postexposure Prophylaxis
Indicated for reducing the severity of chicken pox (varicella zoster virus) infections in high risk individuals after exposure
625 units IM within 10 days after exposure (ideally within 4 days [96 hr])
Consider a second full dose for high risk patients who have additional exposures to varicella >3 weeks after initial administration
Dosing Considerations
High risk groups include
- Immunocompromised patients without evidence of immunity
- Pregnant women without evidence of immunity
Reduces severity only
- There is no convincing evidence that varicella zoster immune globulin (VZIG) reduces the incidence of chickenpox infection after exposure to VZV
- There is no convincing evidence that established infections with VZV can be modified by VZIG administration
- There is no indication for the prophylactic use of VZIG in immunodeficient children or adults when there is a past history of varicella, unless the patient is undergoing bone marrow transplantation
Administration
Inject IM into the deltoid muscle or the anterolateral aspects of the upper thigh
Due to the risk of sciatic nerve injury, do not use the gluteal region as a routine injection site; if gluteal region is used, only use the upper, outer quadrant
Depending on patient size, divide the IM dose and administer in 2 or more injection sites; not to exceed 3 mL/injection site
Pediatric dosage forms and strengths
intramuscular injection
- 125 IU/vial (lyophilized powder)
- 100 IU/mL (after reconstitution)
Varicella, Postexposure Prophylaxis
Indicated for reducing the severity of chicken pox (varicella zoster virus) infections in high risk individuals after exposure
125 IU/10kg IM; not to exceed 625 IU/dose
Administer within 10 days after exposure (ideally within 4 days [96 hr])
<2 kg: 62.5 IU Im
2.1-10 kg: 125 IU Im
10.1-20 kg: 250 IU Im
20.1-30 kg: 375 IU Im
30.1-40 kg: 500 IU Im
>40 kg: 625 IU Im
Consider a second full dose for high risk patients who have additional exposures to varicella >3 weeks after initial administration
Dosing Considerations
High risk groups include
- Immunocompromised patients without evidence of immunity
- Newborn infants whose mothers have signs and symptoms of varicella around the time of delivery (ie, 5 days before to 2 days after)
- Hospitalized premature infants born at 28 weeks of gestation or greater whose mothers do not have evidence of immunity to varicella
- Hospitalized premature infants born at <28 weeks of gestation or who weigh 1 kg or less at birth, regardless of their mothers' evidence of immunity to varicella
Reduces severity
- There is no convincing evidence that varicella zoster immune globulin (VZIG) reduces the incidence of chickenpox infection after exposure to VZV
- There is no convincing evidence that established infections with VZV can be modified by VZIG administration
- There is no indication for the prophylactic use of VZIG in immunodeficient children or adults when there is a past history of varicella, unless the patient is undergoing bone marrow transplantation
Administration
For IM use only
Depending on patient size, divide the IM dose and administer in 2 or more injection sites; not to exceed 3 mL/injection site
Inject IM into the deltoid muscle or the anterolateral aspects of the upper thigh
Due to the risk of sciatic nerve injury, do not use the gluteal region as a routine injection site; if gluteal region is used, only use the upper, outer quadrant
Infants/small children: Administer IM in anterolateral aspect of thigh
VariZIG (varicella zoster immune globulin, human) adverse (side) effects
1-10%
Injection site pain (2%)
Headache (2%)
Frequency not defined
Chills
Fatigue
Rash
Nausea
Thrombosis
Warnings
Contraindications
Anaphylactic or hypersensitivity reactions to human immune globulin preparations
IgA-deficient patients with antibodies against IgA and a history of hypersensitivity may have an anaphylactoid reaction; contains <40 mcg/mL of IgA
Cautions
Thrombotic events reported during or following treatment with immune globulin products; individuals at risk include those with history of atherosclerosis, multiple cardiovascular risk factors, advanced age, impaired cardiac output, coagulation disorders, prolonged periods of immobilization, and/or known/suspected hyperviscosity
For IM administration only; patients with severe thrombocytopenia or any coagulation disorder that would contraindicate IM injections, only administer if the expected benefits outweigh the potential risks
Made from human plasma, may carry risk of transmitting infectious agents (eg, viruses, variant Creutzfeldt-Jakob disease [vCJD] agent)
Pregnancy and lactation
Pregnancy category: C
Lactation: Unknown whether distributed in breast milk
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of VariZIG (varicella zoster immune globulin, human)
Mechanism of action
Solvent/detergent-treated sterile lyophilized preparation of purified human immune globulin G (IgG) containing antibodies to varicella zoster virus
Provides passive immunization for nonimmune individuals exposed to varicella zoster virus, thereby reducing the severity of varicella infections
Absorption
Peak plasma time: 4.5 days
Peak plasma concentration: 136 mIU/mL
AUC: 2472-4087 mIU•day/mL (24-84 days)
Elimination
Half-life: 26.2 days
Total body clearance: 0.204 mL/day
Administration
IM Preparation
Only use the accompanying sterile diluent when reconstituting lyophilized powder
To reconstitute
- Remove caps from the sterile diluent provided and VZIG vials
- Wipe exposed central portion of each rubber stopper with suitable disinfectant
- Withdraw 1.25 mL of the sterile diluent using a suitable syringe and needle
- Inject diluent slowly into the VZIG vial at an angle so that the liquid is directed onto the inside glass wall of the vial containing the freeze-dried pellet
- Wet pellet by gently tilting and inverting the vial to avoid frothing; gently swirl upright vial until dissolved (<10 minutes); DO NOT SHAKE
Inspect visually for particulate matter and discoloration prior to administration
Do not use if turbid and/or discoloration is observed
IM Administration
For IM use only
Depending on patient size, divide the IM dose and administer in 2 or more injection sites; not to exceed 3 mL/injection site
Inject IM into the deltoid muscle or the anterolateral aspects of the upper thigh
Due to the risk of sciatic nerve injury, do not use the gluteal region as a routine injection site; if gluteal region is used, only use the upper, outer quadrant
Infants/small children: Administer IM in anterolateral aspect of thigh
Storage
Unopened vials: Store refrigerated between 2-8°C (36-46°F); do not freeze
Reconstituted vials: Use within 12 hr of reconstitution if stored at 2-8°C; contains no preservative
