Pronunciation: ri-tuk-san
Generic name: rituximab
Brand name: Rituxan
Dosage form: injection for intravenous infusion (100 mg/10 mL, 500 mg/50 mL)
Drug classes: Antirheumatics, CD20 monoclonal antibodies

Medically reviewed by Carmen Pope, BPharm. Last updated on May 5, 2025.

What is Rituxan?

Rituxan infusion is used to treat certain leukemias and lymphomas and some non-cancer conditions, such as rheumatoid arthritis, polyangiitis, and pemphigus vulgaris. It is given by IV infusion (an infusion into a vein) by a healthcare provider.

Rituxan is not chemotherapy, it is a type of immunotherapy called a targeted cancer treatment.

Rituxan gained FDA approval on November 26, 1997. Rituxan has 3 biosimilars: Riabni, Ruxience, and Truxima. A biosimilar is a biological product that is similar to a reference biologic (usually the originally approved product) and for which there are no clinically meaningful differences in terms of safety, purity, and potency.

FDA approvals and indications

Rituxan is approved to treat:

• Non-Hodgkin's lymphoma alone or with other chemotherapy medicines

• Mature B-cell Non-Hodgkin's lymphoma (NHL) and mature B-cell acute leukemia (B-AL) in children 6 months and older, in combination with chemotherapy medicines

• Chronic lymphocytic leukemia in adults, in combination with the chemotherapy medicines fludarabine and cyclophosphamide

• Rheumatoid arthritis (RA) in adults, in combination with methotrexate, to reduce signs and symptoms of moderate to severely active RA after an inadequate response to treatment with a Tumor Necrosis Factor (TNF) antagonist

• Granulomatosis with Polyangiitis (GPA, Wegener's granulomatosis) and Microscopic Polyangiitis (MPA) in adults and children 2 years and older, in combination with glucocorticoids

• Moderate to severe pemphigus vulgaris in adults.

Rituxan is not approved for:

• Children aged less than 2 years with GPA or MPA
• Children less than 6 months of age with mature B-cell NHL and B-AL
• Children with conditions other than GPA, MPA, B-cell NHL, and B-AL.

How Rituxan works

Rituxan is a targeted therapy that attaches to CD20, a protein found on the surface of B cells. As a type of white blood cell in your immune system, B cells normally help fight infections, but they can also contribute to certain diseases. When Rituxan binds to the CD20 protein, it triggers two key mechanisms to destroy these B cells:

1. It activates your body's complement system, which directly attacks and eliminates the B cells
2. It flags the B cells for destruction by other immune cells in a process called antibody-dependent cell-mediated cytotoxicity.

This targeted elimination of B cells makes Rituxan effective for treating various conditions where B cells play a harmful role, including:

• B-cell cancers such as Non-Hodgkin lymphoma and chronic lymphocytic leukemia (CLL)
• Autoimmune disorders like rheumatoid arthritis, where B cells contribute to inflammation and joint damage.

By precisely targeting problematic B cells, rituximab helps control these conditions while minimizing impact on other parts of the immune system.

Side effects

The most common side effects of Rituxan are:

• infusion-related reactions
• infections (may include fever, chills)
• body aches
• tiredness
• nausea.

In adults with GPA or MPA, the most common side effects of Rituxan also include:

• low white and red blood cells
• swelling
• diarrhea
• muscle spasms.

In children with B-cell NHL or B-AL who receive Rituxan with chemotherapy, the most common side effects are:

• decreased white blood cells with fever
• mouth sores
• inflammation of the upper intestine
• serious infection throughout the body and organs (sepsis)
• changes in liver function blood tests
• low level of potassium in the blood

Other side effects of Rituxan are:

• aching joints during or within hours of receiving an infusion
• more frequent upper respiratory tract infections.

These are not all of the possible side effects of Rituxan. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Serious side effects and warnings

Rituxan carries a Boxed Warning for fatal infusion-related reactions, severe skin reactions, hepatitis B virus reactivation, and a rare brain condition called progressive multifocal leukoencephalopathy (PML).

Rituxan can cause the following serious side effects:

• Infusion-related reactions. These are very common side effects of Rituxan treatment. Serious infusion-related reactions can happen during your or your child’s infusion or within 24 hours after. Your healthcare provider should give you or your child medicines before your Rituxan infusion to decrease the chance of having a severe infusion-related reaction. Tell your healthcare provider or get medical help right away if you or your child gets any of these symptoms during or after an infusion:
  • hives (red itchy welts) or rash
  • shortness of breath, difficulty breathing, or wheezing
  • itching
  • weakness
  • swelling of your lips, tongue, throat, or face
  • dizziness or feeling faint
  • sudden cough
  • palpitations (feel like your heart is racing or fluttering)
  • chest pain.
• Severe skin and mouth reactions. Tell your healthcare provider or get medical help right away if you or your child gets any of these symptoms at any time during your treatment with Rituxan:
  • painful sores or ulcers on your skin, lips, or in your mouth
  • blisters
  • peeling skin
  • rash
  • pustules.
• Hepatitis B virus (HBV) reactivation. Before you or your child receives Rituxan treatment, your healthcare provider will do blood tests to check for HBV infection. If you or your child has had hepatitis B or is a carrier of the hepatitis B virus, receiving Rituxan could cause the virus to become an active infection again. Hepatitis B reactivation may cause serious liver problems, including liver failure and death. You or your child should not receive Rituxan if you or your child has active hepatitis B liver disease. Your healthcare provider will monitor you or your child for hepatitis B infection during and for several months after you or your child stops receiving Rituxan. Tell your healthcare provider immediately if you or your child gets worsening tiredness, or yellowing of your or your child’s skin or white part of your eyes, during treatment.
• Progressive Multifocal Leukoencephalopathy (PML). PML is a rare, serious brain infection caused by a virus that can happen in people who receive Rituxan. People with weakened immune systems can get PML. PML can result in death or severe disability. There is no known treatment, prevention, or cure for PML. Tell your healthcare provider right away if you or your child has any new or worsening symptoms or if anyone close to you notices these symptoms:
  • confusion
  • dizziness or loss of balance
  • decreased strength or weakness on one side of your body
  • difficulty walking or talking
  • vision problems.
• Tumor Lysis Syndrome (TLS). TLS is caused by the fast breakdown of cancer cells. TLS can cause you or your child to have:
  • kidney failure and need dialysis treatment
  • an abnormal heart rhythm.

TLS can happen within 12 to 24 hours after an infusion of Rituxan. Your healthcare provider may do blood tests to check you or your child for TLS. Your healthcare provider may give you or your child medicine to help prevent TLS. Tell your healthcare provider right away if you or your child has any of the following signs or symptoms of TLS:

• • nausea
  • diarrhea
  • vomiting
  • lack of energy.
• Serious infections. Serious infections can happen during and after treatment with Rituxan, and can lead to death. Rituxan can increase your or your child’s risk of getting infections and can lower the ability of your or your child’s immune system to fight infections. Types of serious infections that can happen with Rituxan include bacterial, fungal, and viral infections. After receiving Rituxan, some people have developed low levels of certain antibodies in their blood for a long period (longer than 11 months). Some of these people with low antibody levels developed infections. People with serious infections should not receive Rituxan. Tell your healthcare provider right away if you or your child has any symptoms of infection:
  • fever
  • cold symptoms, such as a runny nose or sore throat that do not go away
  • flu symptoms, such as cough, tiredness, and body aches
  • earache or headache
  • pain during urination
  • cold sores in the mouth or throat
  • cuts, scrapes, or incisions that are red, warm, swollen, or painful.
• Heart problems. Rituxan may cause chest pain, irregular heartbeats, and a heart attack. Your healthcare provider may monitor your or your child’s heart during and after treatment with Rituxan if you or your child has symptoms or heart problems or has a history of heart problems. Tell your healthcare provider right away if you or your child has chest pain or irregular heartbeats during treatment with Rituxan.
• Kidney problems, especially if you or your child are receiving Rituxan for NHL. Rituxan can cause severe kidney problems that can lead to death. Your healthcare provider should do blood tests to check how well your or your child’s kidneys are working.
• Stomach and serious bowel problems that can sometimes lead to death. Bowel problems, including blockage or tears in the bowel, can happen if you or your child receives Rituxan with chemotherapy medicines. Tell your healthcare provider right away if you or your child has any severe stomach-area (abdomen) pain or repeated vomiting during treatment with Rituxan.

Your healthcare provider will stop treatment with Rituxan if you have severe, serious, or life-threatening side effects.

Get emergency medical help if you have signs of an allergic reaction to Rituxan, such as hives, difficulty breathing, swelling in your face or throat, or a severe skin reaction (symptoms may include fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

These are not all of the possible side effects of Rituxan. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088

Related/similar drugs

Before taking this medicine

Before you or your child receives Rituxan, tell your healthcare provider about all of your or your child’s medical conditions, including if you or your child:

• have had a severe reaction to Rituxan or a rituximab product
• have a history of heart problems, irregular heartbeat, or chest pain
• have lung, liver, or kidney problems
• have an infection or a weakened immune system
• have or have had any severe infections, including:
  • Hepatitis B virus (HBV)
  • Parvovirus B19
  • Hepatitis C virus (HCV)
  • Varicella zoster virus (chickenpox or shingles)
  • Cytomegalovirus (CMV)
  • West Nile Virus
  • Herpes simplex virus (HSV).
• have had a recent vaccination or are scheduled to receive vaccinations. You or your child should not receive certain vaccines before or during treatment with Rituxan. You should be up-to-date on any needed immunizations before starting treatment with Rituxan.
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

Rituxan may harm an unborn baby. Talk to your healthcare provider about the risks to an unborn baby if you or someone you are caring for receives Rituxan during pregnancy. If you are a female who can become pregnant, your healthcare provider should do a pregnancy test to check for pregnancy before starting Rituxan.

Effective birth control (contraception) should be used during treatment with Rituxan and for 12 months after the last dose. Talk to your healthcare provider about effective birth control.

Tell your healthcare provider right away if you or your child becomes pregnant or think you may be pregnant during treatment with Rituxan.

Breastfeeding

Rituxan may pass into your breast milk. It is not safe to breastfeed a baby while you are using this medicine. Do not breastfeed during treatment and for 6 months after your or your child’s last dose of Rituxan.

How is Rituxan administered?

Rituxan is given by infusion through your or your child’s central catheter or a needle placed in a vein (intravenous infusion), in you or your child’s arm. A healthcare provider will give you this injection.

• Your healthcare provider may prescribe medicines before each infusion of Rituxan to reduce infusion side effects such as fever and chills.
• Rituxan is not given daily. Your Rituxan dosing schedule will depend on the condition being treated. Follow your doctor's dosing instructions very carefully.
• Your healthcare provider should do blood tests regularly to check for side effects of Rituxan.
• Before each Rituxan treatment, your healthcare provider or nurse will ask you questions about your or your child’s general health. Tell your healthcare provider or nurse about any new symptoms.

If you need surgery, tell the surgeon beforehand that you are using this medicine.

Call your doctor at once if you have any of these other side effects, even if they occur several months after you receive Rituxan, or after your treatment ends.

• painful skin or mouth sores, or a severe skin rash with blistering, peeling, or pus;

• redness, warmth, or swelling of the skin;

• severe stomach pain, vomiting, constipation, bloody or tarry stools;

• irregular heartbeats, chest pain or pressure, pain spreading to your jaw or shoulder;

• tiredness or jaundice (yellowing of the skin or eyes);

• signs of infection - fever, chills, cold or flu symptoms, cough, sore throat, mouth sores, headache, earache, pain or burning when you urinate; or

• signs of tumor cell breakdown - confusion, weakness, muscle cramps, nausea, vomiting, fast or slow heart rate, decreased urination, tingling in your hands and feet, or around your mouth.

What happens if I miss a dose?

Call your doctor if you miss an appointment for your Rituxan infusion.

What happens if I overdose?

Since this medication is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving Rituxan?

Do not receive a "live" vaccine while receiving Rituxan, and avoid coming into contact with anyone who has recently received a live vaccine.

There is a chance that the virus could be passed on to you. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), and the nasal flu (influenza) vaccine.

What other drugs will affect Rituxan?

Tell your healthcare provider about all the medicines you or your child takes, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Especially tell your healthcare provider if you or your child takes or has taken:

• a Tumor Necrosis Factor (TNF) inhibitor medicine such as adalimumab, certolizumab, etanercept, or golimumab, infliximab
• a Disease Modifying Anti-Rheumatic Drug (DMARD) such as leflunomide, methotrexate, or sulfasalazine
• chemotherapy drugs, especially cisplatin.

If you are not sure if your or your child’s medicine is one listed above, ask your healthcare provider. This list is not complete. Other drugs may interact with Rituxan, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Rituxan infusion ingredients

Active ingredient: rituximab
Inactive ingredients: polysorbate 80, sodium chloride, sodium citrate dihydrate, and water for injection, USP.

Available as Rituxan injection for infusion, 100 mg/10 mL (10 mg/mL) and 500 mg/50 mL (10 mg/mL) solution in single-dose vials.

Manufacturer

Rituxan (rituximab) is jointly marketed by two pharmaceutical companies, Genentech (a member of the Roche Group) and Biogen.

• Genentech's headquarters are located in South San Francisco, California, USA.
• Biogen's headquarters are located in Cambridge, Massachusetts, USA.

The drug was originally developed through a collaboration between these two companies, and they continue to co-market it in the United States, while Roche markets rituximab internationally under various brand names, including MabThera in many countries.

Rituximab Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for rituximab.

Rituxan biosimilar products

Biosimilar products can only be dispensed in place of the reference product if the healthcare provider specifically prescribes the biosimilar product by name.

Pharmacy laws for biosimilar prescribing may vary by state

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Further information

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