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Trade/other name(s): Rituxan

Why would this drug be used?

This drug is used to treat chronic lymphocytic leukemia and certain types of non-Hodgkin lymphoma. It can also be used for other conditions.

How does this drug work?

Rituximab is a type of immunotherapy known as a monoclonal antibody. A monoclonal antibody is a man-made version of an immune system protein that fits like a lock and key with one certain protein. Rituximab is designed to seek out and lock onto a protein receptor (CD20) found on B lymphocytes (B cells) in the body. Some normal B cells carry this protein, as well as the cancerous ones found in non-Hodgkin lymphoma. When the antibody attaches to the receptor, it sends a signal to the cell to die. It can also bring in other immune cells to help kill the cell.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods. If you have ever reacted to a drug made with mouse proteins, you may be more likely to react to rituximab.
  • If you have any medical conditions such as kidney disease, liver disease, heart disease, congestive heart failure, lung disease, diabetes, or gout. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have ever had infections with certain viruses, including hepatitis B, hepatitis C, herpes virus, varicella zoster virus (which causes chicken pox and shingles), West Nile virus, cytomegalovirus (CMV), or parvovirus B19 (which causes fifth disease). This drug might cause some of these infections to become active again.
  • If you have an active infection. This drug can suppress the immune system, making it harder for your body to fight the infection.
  • If you have had a recent vaccination or are scheduled to get one (see “Precautions”).
  • If you are pregnant, trying to get pregnant, or if there is any chance you might be pregnant. It is not known if this drug might cause problems if either the male or female is taking it at the time of conception or during pregnancy. This drug can pass through the placenta and affect the fetus. Women who are taking this drug should use some kind of birth control during treatment and for 12 months afterward. Check with your doctor about what kinds of birth control can be used with this medicine.
  • If you are breastfeeding. While no studies have been done, this drug may pass into breast milk and affect the baby.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

This drug can interact with the chemotherapy drug cisplatin to cause kidney damage.

Since rituximab may cause the blood pressure to drop, some doctors will ask that you not take blood pressure medicines the day you are due for your treatment.

This drug can lower platelet counts, which can increase the risk of bleeding. Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with rituximab. These include:

  • Vitamin E
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), and many others
  • Warfarin (Coumadin)
  • Ticlopidine (Ticlid)
  • Clopidogrel (Plavix)
  • Dabigatran (Pradaxa)
  • Rivaroxaban (Xarelto)
  • Apixaban (Eliquis)
  • Fondaparinux (Arixtra)
  • Any type of heparin including enoxaparin (Lovenox) and dalteparin (Fragmin)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren’t sure what is in the medicines you take.

Check with your doctor, nurse, or pharmacist about your other medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether some foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Rituximab is given as an injection in a vein (IV). How often it is given depends on why you are getting the drug. The dose depends on your weight and the reason you are getting the drug.

The first infusion is given very slowly (often over several hours) to see if you have a reaction. Later infusions are given a little faster if you did OK during the first one. You will be given medicine before the infusion to help prevent allergic reactions. If you have a reaction, you will probably get other medicine to try and prevent future reactions. Tell your nurse if you begin to feel different at all during the treatment.


This drug can cause allergic reactions in some people when the drug is given, especially with the first treatment. Mild reactions usually consist of fever and chills. More serious reactions happen rarely, but can be dangerous or even fatal. Symptoms can include feeling lightheaded or dizzy (due to low blood pressure), fever or chills, hives, nausea, itching, headache, coughing, shortness of breath, wheezing, tightness in the throat, trouble swallowing, or swelling of the face, tongue, or eyes. Tell your doctor or nurse right away if you notice any of these symptoms during or after being given the drug.

This drug can cause the rapid killing of tumor cells (a condition known as tumor lysis syndrome), which in some cases has led to a serious imbalance of electrolytes in the blood, and even kidney damage within the first 3 days of treatment. It is more likely to occur if there are large numbers of cancer cells in the body, such as at the start of treatment. If your doctor feels you might be at risk, he or she will give you medicines and/or fluids to help prevent it. Let your doctor know right away if you feel weak or faint, have trouble breathing, notice swelling, or have other problems after taking this drug.

This drug can cause kidney damage. This is more common in people who develop tumor lysis syndrome or who get this drug along with the chemotherapy drug cisplatin. Your doctor will check your blood, and may need to stop this drug if signs of kidney problems are seen.

While taking this medicine, and for a few days afterward, there is a slight chance of a serious skin reaction. Symptoms often start as a skin rash with redness, peeling, blisters, or sores. You can also get redness and sores in the mouth, nose, or eyes, along with fever and body aches. If this starts to happen, call your doctor right away as in rare cases these reactions can be fatal.

Rarely, abdominal (belly) pain, blockage of the intestines (obstruction), and even holes (perforations) in the intestines have occurred in people getting rituximab along with chemotherapy. Let your doctor know if you develop severe abdominal pain, nausea, or vomiting, as these can be symptoms of severe problems.

Use of this drug has been linked to a rare brain disease known as progressive multifocal leukoencephalopathy (PML). This disease is caused by a virus and occurs in people with poor immune function. It can lead to seizures, headache, high blood pressure, confusion or change in mental status, loss of vision, and even death. Call your doctor or nurse right away if you have any of these symptoms.

Rarely, patients have developed an irregular heartbeat while getting this drug. Let your healthcare team know if you have a history of heart problems or if you notice a fast or irregular heartbeat or feel like your heart is pounding while the drug is being given. If you do, your doctor may place you on a heart monitor while you are getting this drug. If you develop a serious heart rhythm problem, the drug may need to be stopped.

Your doctor will likely test your blood throughout your treatment, looking for possible effects of the drug on blood counts (described below) or on other body organs. Based on the test results, you may be given medicines to help treat any effects. Your doctor may also need to reduce or delay your next dose of this drug, or even stop it completely.

This drug can lower your white blood cell count, especially in the weeks after the drug is given. It can also lower levels of antibodies in the blood. These can weaken your immune system and increase your chance of getting a serious infection. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° or higher), chills, pain when passing urine, new onset of cough, rash, or bringing up sputum.

This drug may lower your platelet count in the weeks after it is given, which can increase your risk of bleeding. Talk with your doctor before taking any drugs or supplements that might affect your body’s ability to stop bleeding (see “Interactions with other drugs”). Tell your doctor right away if you have unusual bruising, such as nosebleeds, vomit that looks like coffee grounds, bleeding gums when you brush your teeth, or black, tarry stools.

This drug may lower your red blood cell count. If this occurs, it is usually a few weeks after starting treatment. A low red blood cell count (known as anemia) can cause shortness of breath, or make you to feel weak or tired all the time. Your doctor may give you medicines to help prevent or treat this condition, or you may need to get blood transfusions.

Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor's OK. Rituximab may affect your immune system. This could make vaccinations ineffective, or even lead to serious infections if you get live vaccines during treatment or for some time afterward. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine. Check with your doctor about this.

In someone who has ever been infected with the hepatitis B virus, this drug can cause the infection to become active again. This can lead to hepatitis, with problems such as yellowing of the skin and eyes (jaundice), abdominal (belly) pain, poor appetite, weight loss, fatigue, nausea, dark urine, and itching. In severe cases, the liver stops working (liver failure), which can lead to death. If you have any of these signs or symptoms while on this drug, let your health care team know. Your doctor may check your blood for signs of a prior hepatitis infection before starting this drug to see if it is safe.

If you are planning to have surgery (including any type of dental procedure), tell the doctor or dentist that you are taking this drug.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • Mild allergic reaction with first infusion (may include fever, headache, chills, itching, hives, nausea, shortness of breath)*
  • Nausea
  • Infection*

Less common

  • Allergic reaction with second and later infusions (same symptoms as above)
  • Low white blood cell count with increased risk of infection*
  • Low platelet count with increased risk of bleeding*
  • Low red blood cell count (anemia)* which can cause tiredness and weakness
  • Cough
  • Rash, itching
  • Vomiting
  • Diarrhea
  • Back pain
  • Abdominal (belly) pain*
  • Muscle or joint pain
  • Runny nose
  • Low blood pressure


  • Serious allergic reaction, with hives, trouble breathing, tightness in the chest or throat, heart attack, or shock*
  • Serious skin reaction*
  • Kidney damage*
  • Blockage or hole in the bowel, with abdominal (belly) pain*
  • Heart rhythm problems*
  • Death due to allergic reaction, infection, lung damage, tumor lysis syndrome, serious skin rash, bowel obstruction or perforation, kidney failure, liver failure from reactivated hepatitis B, and other causes

*See the “Precautions” section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 1997

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 09/05/2014
Last Revised: 09/08/2014