8 Types of Rituxan Side Effects and How to Manage Them

Rituxan (rituximab) is a monoclonal antibody medication that treats certain blood cancers, such as non-Hodgkin lymphoma and chronic lymphocytic leukemia. This injectable medication works to treat these cancers by targeting and binding to a protein on B cells of the immune system called CD20. This helps stop cancer growth. 

Rituxan can also treat autoimmune conditions such as rheumatoid arthritis and pemphigus vulgaris by suppressing overactive immune systems. In either case, Rituxan is given as an infusion through the vein, typically at an infusion center.

Rituxan is a versatile medication, but it also has many possible side effects. Most side effects are relatively mild, but serious complications can also happen.

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Rituxan side effects at a glance

The most common Rituxan side effects include:

• Infusion reactions

• Lower white blood cell counts

• Infections

• Fever

• Chills

• Weakness

• Nausea

• Headaches

• Night sweats

• Rashes

Rare but serious Rituxan side effects include:

• Severe infusion reactions

• Skin reactions

• Serious infections

• Tumor lysis syndrome (TLS)

• Heart problems, including heart rhythm changes and heart attacks

• Serious stomach problems, like tears in the gut lining

Below, we’ll review more information about eight notable categories of Rituxan side effects and how to manage them.

Good to know: Biosimilars to Rituxan are also available. These medications have similar side effects to Rituxan. A subcutaneous (under-the-skin) formulation of Rituxan — called Rituxan Hycela (rituximab and hyaluronidase) — is also available. But its side effects may differ slightly from what’s described below.

1. Infusion reactions

Rituxan often causes infusion reactions. It’s estimated that over 25% of people who receive Rituxan experience infusion reactions to some degree. Symptoms of a Rituxan infusion reaction can include fever, chills, and itching. Trouble breathing, low blood pressure, and swelling are also possible.

Usually, infusion reactions to Rituxan are mild and gradually improve with each infusion. And they tend to develop within the first 30 minutes to 2 hours of your infusion. But infusion reactions can become severe or life-threatening close to 10% of the time, which we discuss in more detail below. You may be at a higher risk of experiencing a more severe infusion reaction if you have cancer with a high tumor burden or a history of heart or lung problems.

Your healthcare team will likely give you medications before each infusion to lower your chances of experiencing a reaction. Typically, these medications include acetaminophen (Tylenol), a steroid like methylprednisolone, and an antihistamine like diphenhydramine (Benadryl). To manage the increased risk of a reaction during your first infusion, your care team may infuse Rituxan very slowly. If you don't have a serious reaction to your first Rituxan infusion, you'll likely be able to receive your following Rituxan infusions at a faster rate.

2. Infections and lower white blood cell counts

Rituxan can also lower your white blood cell counts. And in turn, lower white blood cell counts can raise your risk of getting an infection. This risk is even higher if you’re also receiving chemotherapy. Common infections reported by people who received Rituxan include colds, upper respiratory tract infections, and urinary tract infections (UTIs).

To lower your risk of an infection, try to avoid being around people who are sick and wash your hands often. Check your temperature regularly to monitor for a fever. And let your healthcare team know if your temperature is 100.4℉ or greater or if you start feeling sick. 

Signs and symptoms of an infection can include:

• Fever

• Chills

• Runny nose

• Sore throat

• Cough

• Unexplained tiredness

• Body aches

• Pain while urinating (for a UTI)

If you do develop an infection, your healthcare team may recommend pausing Rituxan infusions, so they can treat the infection. If you have a serious infection, you may need to stop Rituxan treatment altogether.

3. Fever

Rituxan can cause fever. But it’s often related to an infusion reaction. This type of fever is usually short-lived and can be managed by your healthcare team at the infusion center, typically with acetaminophen.

However, if you develop a fever after you go home, it may be the first sign that an infection is brewing.

4. Stomach upset

Rituxan may upset your stomach, causing symptoms such as nausea, vomiting, and diarrhea. Nausea is more common if you’re receiving Rituxan with chemotherapy.

If you develop nausea or vomiting, let your healthcare team know. They can recommend a nausea medication, such as ondansetron (Zofran) or promethazine (Phenergan), to help manage your symptoms. And if your current nausea medications aren’t doing enough, they can also bolster your nausea medication regimen as needed.

5. Headaches

Headaches are another common side effect of Rituxan. They’re often linked to infusion reactions, as well.

If you experience a headache while receiving Rituxan, let your healthcare team know. They may recommend an over-the-counter (OTC) pain reliever like acetaminophen or ibuprofen (Advil, Motrin), depending on what’s safe for you to take.

Other ways to help manage headaches include drinking plenty of water, catching up on sleep, and lowering stress (when possible).

6. Night sweats

About 15% of people who received Rituxan in initial studies reported experiencing night sweats. Depending on the severity, night sweats may keep you up at night and affect your sleep quality.

Some ways to help manage night sweats include:

• Keeping your bedroom at a cool temperature

• Using lightweight pajamas and bedding

• Limiting your intake of caffeine, alcohol, and spicy food

• Avoiding hot beverages at night

• Exercising regularly

Let your healthcare team know if you have night sweats that become hard to manage on your own. There may be other causes for your symptoms aside from the medication.

7. Tumor lysis syndrome

Certain people with cancer who receive Rituxan are at a higher risk of experiencing a rare but serious side effect called tumor lysis syndrome (TLS). TLS happens when cancer cells break down rapidly. This can lead to dangerously high levels of potassium and uric acid in the body.

TLS is most likely following your first Rituxan infusion. Your healthcare team will proactively check your labs to monitor for signs of TLS. If you do develop TLS, you may need to receive fluids and a medication like allopurinol (Zyloprim) or rasburicase (Elitek) as a remedy. 

Let your healthcare team know without delay if you experience any potential symptoms of TLS, such as sudden tiredness, muscle weakness or cramping, or an abnormal heartbeat.

8. Boxed warnings

Rituxan carries several boxed warnings, the FDA’s most serious medication warning. While boxed warnings can sound scary, your healthcare team will help you manage these risks.

Severe infusion reactions

In rare cases, infusion reactions related to Rituxan can become serious. When they become serious, the reactions can cause severe swelling, trouble breathing, and low blood pressure. Anaphylaxis and respiratory distress have happened, too.

If you experience a severe infusion reaction while receiving Rituxan, your healthcare team will provide you with prompt medical care. This may include administering steroids, epinephrine (Adrenalin), and oxygen. Depending on the severity of the infusion reaction, your healthcare team may recommend permanently stopping Rituxan treatment or attempting the infusion at a slower rate.

Severe skin reactions

In rare cases, Rituxan can also cause severe skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis. These reactions can be life-threatening. If you experience any signs or symptoms of a serious skin reaction — such as painful blisters or skin sores — seek medical attention right away.

Hepatitis B reactivation

If you've had hepatitis B in the past, Rituxan could reactivate residual hepatitis B virus. This could cause another hepatitis B infection.

Your healthcare team will check your hepatitis B status before you start treatment with Rituxan. If you’ve had hepatitis B in the past, you may need to receive antiviral treatment as a precaution. If you have an active hepatitis B infection, you shouldn't receive Rituxan.

Progressive multifocal leukoencephalopathy

Although rare, Rituxan can cause a serious brain condition called progressive multifocal leukoencephalopathy (PML). Your risk of developing PML is higher if you’re also receiving chemotherapy or are receiving Rituxan for a stem cell transplant. 

Let your healthcare team know right away if you experience PML symptoms such as weakness, difficulty walking, or difficulty speaking.

When to contact a healthcare professional about Rituxan side effects

Most of Rituxan’s common side effects are relatively mild. But you should still contact your healthcare team (at your convenience) if you’re experiencing any bothersome side effects.

If you develop any severe or life-threatening symptoms, it’s important to get medical help right away. This includes:

• Symptoms of a severe infusion reaction, such as swelling, trouble breathing, or low blood pressure

• Symptoms of an infection, such as fever, chills, or cough

• Signs of hepatitis B reactivation, such as fever, tiredness, or yellowing of the skin and eyes

• Symptoms of PML, such as difficulty walking, difficulty speaking, or weakness

• Skin peeling or blistering

• Chest pain or an irregular heartbeat

• Severe stomach upset

Why trust our experts?

Written by:

Sonja Jacobsen, PharmD, BCPS, BCOP

Sonja Jacobsen, PharmD, BCPS, BCOP,  is a clinical oncology pharmacy specialist currently practicing in Seattle. She has been practicing as a pharmacist since 2015 and is licensed to practice in Washington state and North Carolina.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Vanessa Carranza, PharmD

Vanessa Carranza, PharmD, is a pharmacist who has dedicated her career to the advancement of medical education for healthcare providers, patients, and caregivers, most notably in the oncology space.

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