Varizig is the brand name for varicella zoster immune globulin. It's FDA-approved to lessen the severity of chickenpox in adults and children who are at risk for serious illness. Varizig isn't a vaccine. Instead, it contains antibodies that fight against the varicella zoster virus, which causes chickenpox. Varizig is given as an injection into the muscle of the shoulder or upper thigh by a healthcare provider. It works best if it's given within 4 days of exposure to chickenpox. Common side effects include pain at the injection site and headache.
Prevent or lessen the severity of chickenpox after exposure to the varicella-zoster virus in certain high-risk people
Varizig (varicella zoster immune globulin) is an immune globulin that protects you from getting seriously sick after you've been exposed to chickenpox. It's an antibody that works by attaching to the varicella-zoster virus (the virus that causes chickenpox) in your body to help your body attack and destroy it.
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor or nurse immediately if any of the following side effects occur:
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Typically only need to get 1 dose
Side effects are rare
Possible option during pregnancy
Can only be given as an injection into the muscle
Can only be given by a healthcare provider
Need to wait at least 3 months before receiving live vaccines
Varizig (varicella zoster immune globulin) is used to prevent severe chickenpox infection. If you develop signs or symptoms of chickenpox, contact your provider right away. Receiving Varizig (varicella zoster immune globulin) within 4 days of exposure might help provide the best protection against chickenpox.
Mark your appointment dates on your calendar for all your Varizig (varicella zoster immune globulin) injections. Getting your injections on time helps make sure you can stay fully protected against chickenpox.
Don't receive any vaccines, especially live vaccines, without talking to your provider or pharmacist first to make sure it's safe for you to get them. Varizig (varicella zoster immune globulin) can affect how your body responds to certain vaccines.
If you weigh 44 pounds or more, your total dose will be split into at least 2 injections at different areas of your body.
Varizig (varicella zoster immune globulin) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Atherosclerosis (fatty buildup in the arteries) | High triglycerides (fat) | Risk factors for heart problems | Heart failure | Clotting problems | Older adults | Not moving for long periods of time | High blood thickness (viscosity)
There's a risk of blood clots during or after treatment with immune globulins, like Varizig (varicella zoster immune globulin). Your provider will check for any risk factors for clots listed above, such as atherosclerosis or other risk factors for heart problems. Also be sure to tell your providers about all your medical conditions. Watch out for symptoms of a blood clot, which can differ depending on the location of the clot. Get medical help if you feel symptoms such as chest pain, trouble breathing, and numbness or weakness on one side of the body.
Varizig (varicella zoster immune globulin) is given as an injection into the muscle. Talk to your provider before you get Varizig (varicella zoster immune globulin) if you have a history of a low platelet count or a coagulation (clotting) problem. Injections into the muscle aren't usually recommended for people with these conditions for safety reasons. Varizig (varicella zoster immune globulin) should only be given to you if the benefit is greater than the risk.
Risk factors: Antibodies to IgA
There's a rare chance that you might have a severe allergic reaction to Varizig (varicella zoster immune globulin). Your risk is higher if you have antibodies to IgA because Varizig (varicella zoster immune globulin) contains a low amount of IgA, which might trigger a reaction.
Your provider might ask you to stay at the hospital or clinic for a short period of time after you've gotten your dose of Varizig (varicella zoster immune globulin) to make sure you can get proper care in case of a serious allergic reaction. Sometimes, these reactions can happen after you've already left the clinic. Get medical help right away if you notice symptoms of a severe allergic reaction, such as feeling faint, swelling of the face, closing of the throat, difficulty breathing, hives or rash, dizziness, shaking, nausea, or chest pain.
Varizig (varicella zoster immune globulin) is made from human plasma, which is taken from human blood. Although very rare, there's a possible risk that viruses might be passed onto people receiving this medication and put them at risk for conditions such as Creutzfeld-Jakob Disease (CJD). Before Varizig (varicella zoster immune globulin) is made, many steps are taken to lower this risk: blood donors are screened, the blood is tested for infections, and the blood product is processed to remove or inactivate certain viruses. Please note that this risk is only a theory, and known cases haven't been reported in real life. If you have concerns, speak to your provider. If your provider suspects an infection from Varizig (varicella zoster immune globulin), they should report it by calling 1-833-644-4216.
Your provider will calculate your dose based on your body weight. The typical dose ranges from 62.5 to 625 international units (IU) injected into the muscle once, typically in the shoulder or thigh, by a healthcare provider. Depending on your dose, your provider might divide it and inject it in two or more injection sites.
Your might give you a second dose of Varizig (varicella zoster immune globulin) if you've been exposed to chickenpox again after more than 3 weeks since your first Varizig (varicella zoster immune globulin) dose.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Severe allergic reactions to other human immune globulins
A lack of immunoglobulin A in the blood and a history of allergic reaction
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Centers for Disease Control and Prevention. (n.d.). Chickenpox (varicella).
Centers for Disease Control and Prevention. (2024). Classic Creutzfeldt-Jakob disease.
Centers for Disease Control and Prevention. (2013). Updated recommendations for use of VariZIG — United States, 2013. Morbidity and Mortality Weekly Report (MMWR).
MedlinePlus. (2022). Immunoglobulins blood test.
Medline Plus. (2022). Selective deficiency of IgA.
National Heart, Lung, and Blood Institute. (2022). Thrombocytopenia.
National Heart, Lung, and Blood Institute. (2022). What are blood clotting disorders?
Saol Therapeutics. (2023). Varizig- human varicella-zoster immune globulin solution [package insert]. DailyMed.
Sidhu, A. S., et al. (2024). Varicella-zoster immune globulin. StatPearls.
World Health Organization. (2020). How do vaccines work?
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