If you have a certain kind of cancer, your doctor might suggest Gazyva (obinutuzumab) as a treatment option for you. So you may be wondering about the possible side effects of this treatment.

Gazyva is a prescription drug that’s used in adults to treat certain forms of:

Gazyva is a biologic drug that’s a targeted therapy for these kinds of cancer. (Biologics are made from parts of living organisms.) It’s usually prescribed with chemotherapy (traditional drugs used to treat cancer) for about 6 months. For FL, you might also receive Gazyva on its own for up to 2 years more.

You’ll receive Gazyva by intravenous (IV) infusion (an injection into a vein that’s given over a period of time). A healthcare professional will give you the infusions in a hospital or infusion center. How often you’ll have the infusion depends on your condition.

For more information about Gazyva, including details about its uses, see this in-depth article.

Like other drugs, Gazyva can cause mild or serious side effects (also referred to as adverse effects). Keep reading to learn more.

Some people may experience mild or serious side effects during Gazyva treatment. Examples of Gazyva’s more commonly reported side effects include:

* To learn more about this side effect, see the “Side effects explained” section below.

Examples of mild side effects that have been reported with Gazyva include:

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop receiving Gazyva unless your doctor recommends it.

Gazyva may cause mild side effects other than the ones listed above. See the Gazyva prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Gazyva, visit MedWatch.

Serious side effects that have been reported with Gazyva include:

* Gazyva has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.
† To learn more about this side effect, see the “Side effects explained” section below.

If you develop serious side effects while receiving Gazyva, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Get answers to some frequently asked questions about Gazyva’s side effects.

Can Gazyva cause long-term side effects?

Yes, it can. Some of Gazyva’s serious side effects can last for a long time. For example, it may take several months for low white blood cell levels to return to normal after stopping Gazyva treatment. And some infections can last for a long time, even when treated with antibiotics or antivirals.

But most of Gazyva’s side effects get better within a few days or weeks of stopping treatment.

Note that receiving Gazyva for a long period of time doesn’t seem to increase the risk of developing side effects. In fact, some side effects, such as infusion reactions, become less likely with each dose of the drug.

If you have questions about possible long-term side effects with Gazyva, talk with your doctor.

Does Gazyva cause hair loss?

It’s not known to cause hair loss. This side effect wasn’t reported in studies of Gazyva. But Gazyva is prescribed together with chemotherapy (traditional drugs used to treat cancer), and chemotherapy commonly causes hair loss. Hair usually starts to regrow after you stop chemotherapy.

If you’re concerned about hair loss caused by chemotherapy, talk with your doctor about ways to manage this.

Will I need any monitoring for side effects while receiving Gazyva?

Yes, you will. Your doctor will give you various blood tests from time to time to monitor you for possible side effects of Gazyva. This can help avoid serious problems developing during treatment. Tests your doctor may order include:

You may also need other monitoring from time to time.

Learn more about some of the side effects Gazyva may cause.

Hepatitis B reactivation

Gazyva has a boxed warning for hepatitis B reactivation. A boxed warning is a serious warning from the Food and Drug Administration (FDA).

If you’ve ever had an infection with the hepatitis B virus (HBV), receiving Gazyva could make this virus active in your body again. This is because HBV can stay in your body for a long time, even if you’ve taken medication to treat it. Gazyva makes it harder for your body to fight germs that cause infections.

It may be possible for HBV to reactivate while you receive Gazyva and for several months after you stop treatment. This could lead to hepatitis B, liver failure, and, in rare cases, death.

Symptoms of hepatitis B can include:

What might help

Your doctor will test you for HBV before you start treatment with Gazyva. If HBV is detected, you may need to take an antiviral treatment for hepatitis B before you can start receiving Gazyva.

If you have symptoms of hepatitis B while you’re receiving Gazyva or after you’ve stopped, tell your doctor right away. You’ll likely need to stop receiving Gazyva (if you’re still receiving it) and start treatment for hepatitis B.

Progressive multifocal leukoencephalopathy

Gazyva has a boxed warning for a rare brain disease called progressive multifocal leukoencephalopathy (PML). A boxed warning is a serious warning from the FDA.

Gazyva can increase the risk of developing PML. This disease is caused by a rare viral infection of the brain, and it can lead to death.

Symptoms of PML may include:

What might help

If you have any symptoms of PML during Gazyva treatment, contact your doctor right away. You may need to have tests such as brain scans to check for this side effect.

If you develop PML, you’ll need to stop receiving Gazyva.

Infusion reactions

Gazyva can cause infusion reactions. These are side effects that happen during your infusion or in the 24 hours after. They’re usually mild, but they can sometimes be severe or even life threatening.

Symptoms of a mild infusion reaction may include:

  • fever
  • chills
  • rash
  • diarrhea
  • nausea or vomiting
  • low energy
  • chest discomfort
  • throat irritation
  • dizziness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • headache

Symptoms of a severe infusion reaction may include:

It’s common to have an infusion reaction with the first dose of Gazyva. But you’re less likely to have a reaction with each subsequent dose. And severe reactions are rare after the first dose.

If you have a heart or lung condition, you may be more likely to have a severe infusion reaction.

What might help

To help prevent infusion reactions, a healthcare professional will usually give you certain medications before your infusion. Before your first dose of Gazyva, you’ll usually take:

If you have a mild reaction with your first dose of Gazyva, you may only need acetaminophen and an antihistamine before future doses. But if you don’t have any reaction with your first dose, you’ll likely only need acetaminophen before future doses.

If you take blood pressure medication, your doctor may recommend pausing it around the time you receive a Gazyva dose. This can help prevent your blood pressure from dropping too low. Your doctor may recommend that you don’t take blood pressure medication in the 12 hours before you have a Gazyva infusion. And they’ll tell you when to restart it after your infusion.

You’ll be monitored for infusion reactions during and after your infusion. If you have symptoms of a reaction, tell your doctor right away. Depending on how severe your symptoms are, they may slow down or temporarily stop your infusion. But if you have a severe reaction, your doctor may decide that you shouldn’t continue treatment with Gazyva.

Decreased numbers of white blood cells

Gazyva commonly decreases the number of white blood cells in your blood. Note that chemotherapy (traditional drugs used to treat cancer), which you may be having with Gazyva, can also cause this side effect. The kinds of cancer Gazyva treats can also cause low white blood cell counts.

White blood cells help your body fight infections. If you have low numbers of these cells, you have a higher risk of getting infections. Infections may be mild, such as coughs, colds, cold sores, or minor urinary tract infections (UTIs). But they can also be more serious, such as pneumonia or shingles.

Symptoms of a low white blood cell count may include:

What might help

During treatment with Gazyva, you’ll have frequent blood tests to check your white blood cell levels. If you have any symptoms of a low white blood cell count, tell your doctor right away so that they can check for this.

If your white blood cell numbers drop too low, your doctor may prescribe antifungal or antiviral medication to help prevent infections. They may also prescribe a medication called granulocyte-colony stimulating factor, such as Neulasta (pegfilgrastim), to help increase your white blood cell numbers.

It’s a good idea to take simple measures to help prevent infections while receiving Gazyva. These include washing your hands often, staying away from people who are sick, and avoiding crowds.

Allergic reaction

Like most drugs, Gazyva can cause an allergic reaction in some people.

Symptoms can be mild or serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. To manage your symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine). Or they may recommend a product you apply to your skin, such as hydrocortisone cream.

If your doctor confirms you had a mild allergic reaction to Gazyva, they’ll decide if you should continue receiving it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you had a serious allergic reaction to Gazyva, they may have you switch to a different treatment.

Keeping track of side effects

During Gazyva treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how Gazyva affects you. And your doctor can use this information to adjust your treatment plan if needed.

Gazyva is not suitable for everyone and comes with several warnings.

Boxed warnings

Gazyva has boxed warnings about hepatitis B reactivation and progressive multifocal leukoencephalopathy (PML). Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA).

  • Hepatitis B reactivation. If you’ve ever contracted the hepatitis B virus, Gazyva could make the virus active in your body again. This could lead to liver failure and, in rare cases, death.
  • PML. Gazyva can increase the risk of developing PML, a rare brain disease. PML can lead to death.

To learn more about these side effects, including symptoms to look out for, see the “Side effects explained” section above.

Other warnings

Gazyva may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you receive Gazyva. The list below includes factors to consider.

Tumor lysis syndrome. Gazyva can cause tumor lysis syndrome, a serious side effect. If you have kidney problems or a high number of cancer cells, you may have an increased risk of tumor lysis syndrome. Your doctor may prescribe extra medication to help prevent this side effect. Drinking plenty of fluids during treatment may also help.

Infection. Gazyva can make it harder for your body to fight infections. If you currently have an infection, it will need to be treated before you receive Gazyva. And if you have a history of long-term or recurring infections, you may be more likely to have infections while receiving Gazyva. Talk with your doctor about any infections you have now or have had in the past.

Vaccines. You shouldn’t get live vaccines while you’re having treatment with Gazyva or for a few months afterward. Live vaccines contain a weakened form of virus or bacteria. Examples include the chickenpox, yellow fever, and typhoid vaccines. These vaccines don’t usually cause infections, but they could if you’re having treatment with Gazyva. This is because the drug makes it harder for your body to fight infections. It’s recommended that you’re up to date with all your vaccines before you start Gazyva.

Allergic reaction. If you’ve had an allergic reaction to Gazyva or any of its ingredients, your doctor will likely not prescribe Gazyva. Ask your doctor what other medications are better options for you.

Alcohol and Gazyva

Alcohol isn’t known to interact with Gazyva. But if you have certain side effects, such as headache, diarrhea, or dizziness, drinking alcohol might make them worse.

If you drink alcohol, ask your doctor how much is safe to consume while you’re receiving Gazyva.

Pregnancy and breastfeeding while taking Gazyva

Your doctor will likely recommend that you don’t receive Gazyva while you’re pregnant because it could have harmful effects on a developing fetus. If you’re pregnant or planning to become pregnant, talk with your doctor about the pros and cons of receiving this drug.

If you can become pregnant, you should use effective birth control to help prevent pregnancy during treatment with Gazyva. And you should keep using birth control for 6 months after stopping Gazyva treatment.

It’s not known if Gazyva is safe to receive while breastfeeding. It’s recommended that you don’t breastfeed during treatment or for 6 months afterward. If you’re breastfeeding, talk with your doctor about other ways to feed your child during Gazyva treatment.

As with most cancer treatments, it’s common to have side effects with Gazyva. Most of these are mild or easily managed, but some can be serious. And note that you’ll receive Gazyva with chemotherapy (traditional drugs used to treat cancer), which can also cause some serious side effects.

If you’d like to know more about the risk of side effects with Gazyva, talk with your doctor. They can help you decide if this treatment is a good option for you. Here are a few questions you might want to ask them:

  • Do I have a higher risk of side effects with Gazyva than other people?
  • Are there things I can do to lower my risk of side effects?
  • Do I need to get any vaccines before starting Gazyva?
  • Do I need to stop taking my other medications before Gazyva infusions?
  • Does Gazyva increase my risk of getting COVID-19? Can I get a COVID-19 vaccine while receiving it?


What should I do if I get a cold during Gazyva treatment?



If you get a cold during Gazyva treatment, tell your doctor. They’ll check your symptoms, such as whether you have a fever, and possibly have you get blood work.

Based on what they find, they may choose to postpone your next scheduled infusion until you feel better. Or they may change the medications you take before you receive your Gazyva infusion.

For cold symptoms that are bothersome, ask your doctor or pharmacist to recommend medication to help ease your symptoms.

If you feel unwell during Gazyva treatment, be sure to let your doctor know.

Dena Westphalen, PharmDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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Disclaimer: Healthline 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.