Gamunex-C: Dosage, side effects, uses, interactions, cost, and more
Gamunex-C is a brand-name infusion prescribed for certain immune system conditions. Gamunex-C contains the active ingredient immune globulin (human) and belongs to the immune globulin drug class.
Gamunex-C has boxed warnings. A boxed warning is the most serious warning from the FDA. For details, see the “Gamunex-C precautions” section.
Gamunex-C is available only as a brand-name medication. It’s not currently available in biosimilar form.
A biosimilar medication is a medication that’s similar to a brand-name biologic drug (also called the reference drug). Gamunex-C is a biologic medication, which is also called a biologic.
Biologic drugs are made from living cells. It isn’t possible to make an exact copy of a biologic. A generic, on the other hand, refers to drugs made from chemicals. Because brand-name nonbiologic medications are also made from chemicals, generics are exact copies of the active ingredient in a brand-name nonbiologic medication.
Biosimilars are considered to be as safe and effective as their reference drug. Similar to generics, biosimilars typically cost less than brand-name biologic medications.
The following information describes dosages that are commonly used or recommended. However, your doctor will determine the best dosage to fit your needs.
Gamunex-C comes as a solution for either intravenous or subcutaneous infusion (a type of injection given over time) inside single-use vials, available in the following strengths:
For treating primary humoral immunodeficiency (PI), also called primary humoral immunodeficiency disease (PIDD), Gamunex-C may be given as either an intravenous (IV) or subcutaneous infusion by a healthcare professional. Your doctor may also teach you to give Gamunex-C subcutaneous infusions at home using an infusion pump.
When given as an IV infusion for treating PI, the recommended Gamunex-C dosage is 300 mg to 600 mg per kilogram (kg) of body weight (300 to 600 mg/kg) injected once every 3 to 4 weeks. For reference, 1 kg is about 2.2 pounds (lb).
For example, a person weighing 170 lb is about 77 kg. If their doctor prescribes 400 mg/kg every 3 to 4 weeks, their Gamunex-C dosage would be about 30,800 mg (30.8 g) infused every 3 to 4 weeks.
When given as a subcutaneous infusion for treating PI, Gamunex-C is infused once per week. The recommended Gamunex-C dosage depends on your previous dose of IV Gamunex-C. If you haven’t previously received IV Gamunex-C, your doctor will determine an IV dosage for you. They will use the process described in “Gamunex-C IV dosage for PI” to calculate your subcutaneous infusion dosage.
For example: a 170-lb person weighs about 77 kg, and their monthly IV Gamunex-C dosage is 30,800 mg (30.8 g). To calculate the subcutaneous infusion Gamunex dosage, the doctor will multiply 30.8 g by 1.37, which equals about 42.2 g. Then, they’ll divide this number by 3 or 4 (depending on the number of weeks between IV Gamunex-C doses). Dividing 42.2 g by 4 weeks gives a weekly subcutaneous infusion Gamunex-C dose of 10.5 g infused once weekly.
For treating idiopathic thrombocytopenic purpura (ITP), also known as immune thrombocytopenic purpura, Gamunex-C is only given as an IV infusion by a healthcare professional. It should not be infused subcutaneously for treating this condition.
The recommended Gamunex-C dosage for treating ITP is a total dose of 2 g/kg body weight. This dose may be divided into:
For example: a 170-lb person weighs about 77 kg. Their doctor would prescribe an IV Gamunex-C dose of 154 g, which would be divided into either:
For treating CIDP, a healthcare professional gives Gamunex-C as an IV infusion. The medication is not infused subcutaneously for treating this condition.
The recommended Gamunex-C dosage for treating CIDP may involve a loading dose and a maintenance dose. With a loading dose, a large amount of medication is given to “load” the body with the medication to help it work quickly.
The recommended Gamunex-C loading dose for treating CIDP is 2 g/kg body weight, given in divided doses over 2 to 4 consecutive days.
The recommended Gamunex-C maintenance dose is 1 g/kg body weight, given either as one dose over 1 day or divided into two doses given on 2 consecutive days. This maintenance dose is given every 3 weeks.
For example: a 170-lb person weighs about 77 kg.
The dosage for Gamunex-C when used in children to treat PI or ITP is the same as the weight-based dosing for adults described in “Dosage for primary humoral immunodeficiency (PI)” and “Dosage for idiopathic thrombocytopenic purpura (ITP).”
Talk with your child’s doctor or pharmacist if you have questions or would like to know more about children’s dosages for Gamunex-C.
Gamunex-C may be given as either a subcutaneous infusion or an IV infusion by a healthcare professional. How Gamunex-C is infused depends on the condition it’s prescribed to treat:
When used as a subcutaneous infusion for treating PI, your healthcare professional may train you to give yourself infusions at home using an infusion pump. They’ll train you to use a needle and syringe to draw Gamunex-C from the vial and use it to fill the infusion pump. They’ll also train you to use the infusion pump to deliver each Gamunex-C dose.
When used as an IV infusion, a healthcare professional will give you your Gamunex-C doses at a site such as an infusion clinic or your doctor’s office. You may also receive visits from a home care provider to give these infusions at your home. IV Gamunex-C infusions typically last about 2 to 4 hours each.
You can view step-by-step instructions on using the infusion pump in Gamunex-C’s prescribing information. You can also ask your doctor or pharmacist for assistance.
Using more than the recommended dosage of Gamunex-C can lead to serious side effects. Do not use more Gamunex-C than your doctor recommends.
If you think you’ve taken too much of this drug, call your doctor. You can also call America’s Poison Centers at 800-222-1222 or use its online tool. However, if your symptoms are severe, call 911 or your local emergency number or go to the nearest emergency room right away.
Gamunex-C can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Gamunex-C. These lists do not include all possible side effects.
It’s important to note that side effects reported with Gamunex-C can differ slightly in people with primary humoral immunodeficiency (PI), idiopathic thrombocytopenic purpura (ITP), and chronic inflammatory demyelinating polyneuropathy (CIDP).
For more information about the possible side effects of Gamunex-C, talk with your doctor or pharmacist. They can give you tips on how to manage any side effects that may be concerning or bothersome.
Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking Gamunex-C and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.
Here is a partial list of mild side effects of Gamunex-C. To learn about other mild side effects, talk with your doctor or pharmacist, or view Gamunex-C’s prescribing information.
In addition, abdominal pain has also been reported when Gamunex-C is administered subcutaneously to treat PI/PIDD.
Most of these side effects may go away within a few days to a couple of weeks. However, if they become more severe or don’t go away, talk with your doctor or pharmacist.
Serious side effects from Gamunex-C aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 or your local emergency phone number if your symptoms feel life threatening or you think you’re having a medical emergency.
* Gamunex-C has a boxed warning for this side effect. This is the most serious warning from the FDA. To learn more, see the “Gamunex-C precautions” section.
Side effects in children are similar to those reported in adults treated with Gamunex-C described previously, with some exceptions:
For some people, Gamunex-C can cause an allergic reaction.
In general, symptoms of an allergic reaction can be mild or serious.
For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.
For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Gamunex-C, your doctor may recommend a different medication instead.
Primary humoral immunodeficiency (PI) is also called primary humoral immunodeficiency disease (PIDD). PI, or PIDD, is a genetic condition that causes part of the immune system to be missing or not function properly. This increases the risk of infection and causes people with PI to be sick with infections frequently.
There are over 450 different types of PI or PIDD, including X-linked agammaglobulinemia and Wiskott-Aldrich syndrome.
With idiopathic thrombocytopenic purpura (ITP), also known as immune thrombocytopenic purpura, your immune system mistakenly attacks and destroys healthy platelets in your body. Platelets are cells your body uses to form blood clots and help heal wounds. Without enough platelets, you’re at increased risk of excessive bleeding that can be severe.
Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare autoimmune condition where the immune system mistakenly damages and destroys tissue within the nerves. This nerve damage can affect a host of bodily functions, including the ability to move and feel.
Symptoms of CIDP may remain stable, or may occur in flares or episodes (where symptoms suddenly worsen for some period of time).
Gamunex-C is not approved for treating CIDP in children, but is used to treat this condition in adults.
Gamunex-C can interact with certain vaccines and lab tests.
Before taking Gamunex-C, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.
Here is a list of vaccines and lab tests that can interact with Gamunex-C. This list does not contain all drugs that may interact with Gamunex-C. If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.
Alcohol is not known to interact with Gamunex-C. But alcohol can worsen idiopathic thrombocytopenic purpura (ITP) and primary humoral immunodeficiency (PI), two conditions Gamunex-C is prescribed to treat. If you drink alcohol and you’re using Gamunex-C to treat PI or ITP, your doctor may advise you to minimize or avoid alcohol consumption.
If you have questions about how much alcohol is safe to drink while taking Gamunex-C, talk with your doctor or pharmacist.
As with all medications, the cost of Gamunex-C can vary. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.
Financial and insurance assistance: If you need financial support to pay for Gamunex-C or help understanding your insurance coverage, help is available.
The Gamunex Connexions support program is available for Gamunex-C. For more information and to find out whether you’re eligible for support, call 888-694-2686 or visit the program website.
Generic or biosimilar version: Gamunex-C is not available in a biosimilar form. A biosimilar refers to a medication that’s similar to a brand-name biologic medication (also called the reference drug). Gamunex-C is a biologic medication, which is also called a biologic.
Biologics such as Gamunex-C are made from living cells. It is not possible to make an exact copy of a biologic drug. A generic, on the other hand, refers to medications made from chemicals. Because brand-name nonbiologic medications are also made from chemicals, generics are exact copies of the active ingredient in a brand-name medication.
Biosimilars are considered to be as safe and effective as their reference drug. And like generics, biosimilars typically cost less than brand-name biologic medications.
Other drugs are available that can treat your condition. Some may be a better fit for you than others. If you’re interested in finding an alternative to Gamunex-C, talk with your doctor. They can tell you about other medications that may work well for you.
You may wonder how Gamunex-C compares with other medications that are prescribed for similar uses, such as Gammaked.
Gamunex-C and Gammaked both contain human immune globulin as their active ingredient (what makes a drug work). Both medications have boxed warnings about the risk of blood clots, worsening kidney function, and kidney failure. They’re both prescribed to treat the same conditions:
Talk with your doctor or pharmacist if you’d like to know more about how Gamunex-C and Gammaked compare.
If you can become pregnant, consider the following information about pregnancy, birth control, and breastfeeding.
It’s not known whether Gamunex-C should be used during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before receiving this medication.
It’s not known whether Gamunex-C is safe to take during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control options while you’re using Gamunex-C.
It’s not known whether Gamunex-C should be used while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before receiving this medication.
It’s not fully understood exactly how Gamunex-C works to treat PI, ITP, or CIDP.
Gamunex-C contains antibodies, which are proteins that help your body protect itself from infection. For treating PI, one theory is that Gamunex-C supplies antibodies that are missing or in short supply, which may help protect against infection. But more research is needed to fully understand how the drug works, especially for treating ITP or CIDP.
There are certain precautions to consider before starting treatment with Gamunex-C. These are discussed in detail here.
This drug has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.
Risk of blood clots: Treatment with immune globulin medications, including Gamunex-C, can cause blood clots as a side effect. While rarely reported in studies of Gamunex-C, blood clots can be life threatening or even fatal.
Blood clots can happen to anyone treated with Gamunex-C, but certain risk factors can increase the risk of this side effect from treatment. These risk factors include having a blood clot in the past, being age 65 years or older, and being immobile for a long period of time.
To lower the risk of blood clots, your doctor will infuse Gamunex-C at the lowest dose and slowest rate necessary to treat your condition. They’ll also make sure you’re properly hydrated before each dose. If you’re using Gamunex-C subcutaneously at home, follow your doctor’s instructions for using the drug to lower your risk of blood clots.
If you think you’re experiencing symptoms of a blood clot that seem serious or life threatening, seek emergency medical attention, such as calling 911 or your local emergency number.
Risk of worsening kidney function and kidney failure: Treatment with immune globulin medications, including Gamunex-C, is reported to cause worsened kidney function in rare cases and acute kidney failure as side effects. These side effects can happen to anyone treated with Gamunex-C, but certain people are at higher risk due to certain risk factors. These risk factors include:
To lower your risk of kidney-related side effects, your doctor will infuse Gamunex-C at the slowest rate necessary to treat your condition. Your doctor should test your kidney function prior to prescribing Gamunex-C and periodically throughout your treatment. They’ll also make sure you’re properly hydrated before each dose.
If you’re using Gamunex-C subcutaneously at home, follow your doctor’s instructions for using the drug to lower your risk of worsened kidney function and kidney failure.
Immediately report symptoms of worsening kidney function to your doctor during your treatment with Gamunex-C. Your doctor can determine whether you should stop using the drug and treat your kidney-related side effect.
Before taking Gamunex-C, discuss your health history with your doctor. Gamunex-C may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:
Note: For more information about the potential negative effects of Gamunex-C, see the “Gamunex-C side effects” section.
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.