Rituximab belongs to a class of medications called monoclonal antibodies. It is used to treat non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL) and works by killing cancer cells. Certain rituximab injection brands also treat rheumatoid arthritis, granulomatosis with polyangiitis, microscopic polyangiitis, and pemphigus vulgaris by blocking the activity of the part of the immune system that may damage the joints, veins, and other blood vessels.

Rituximab is used in adults alone or with other medications to treat various types of non-Hodgkin's lymphoma (a type of cancer that begins in a type of white blood cells that normally fights infection).

Rituximab is also used in adults with other medications to treat chronic lymphocytic leukemia (a type of cancer of the white blood cells).

Rituximab (Rituxan, Ruxience, Truxima) is also used in adults with methotrexate (Otrexup, Rasuvo, Xatmep, others) to treat the symptoms of rheumatoid arthritis (RA; a condition in which the body attacks its own joints, causing pain, swelling, and loss of function) in adults who have already been treated with a certain type of medication called a tumor necrosis factor (TNF) inhibitor.

Rituximab (Rituxan, Riabni, Ruxience, Truxima) is also used in adults and children 2 years of age and older along with other medications to treat granulomatosis with polyangiitis (Wegener's granulomatosis) and microscopic polyangiitis, which are conditions in which the body attacks its own veins and other blood vessels, which causes damage to organs, such as the heart and lungs.

Rituximab injection (Rituxan) is used to treat pemphigus vulgaris (a condition that causes painful blisters on the skin and the lining the mouth, nose, throat and genitals).

Rituximab may cause a serious brain infection that can lead to disability or death. Call your doctor right away if you have problems with speech, thought, vision, or muscle movement. These symptoms may start gradually and get worse quickly.

Tell your doctor if you have ever had hepatitis B. Rituximab can cause this condition to come back or get worse.

Severe skin problems can also occur during treatment with rituximab. Call your doctor if you have painful skin or mouth sores, or a severe skin rash with blistering, peeling, or pus.

Some side effects may occur during the injection or within 24 hours afterward. Tell your caregiver right away if you feel itchy, dizzy, weak, light-headed, short of breath, or if you have chest pain, wheezing, sudden cough, or pounding heartbeats or fluttering in your chest.

Rituximab is given as an infusion into a vein. A healthcare provider will give you this injection.

Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using rituximab.

Rituximab is not given daily. Your schedule will depend on the condition being treated. Follow your doctor's dosing instructions very carefully.

Before each injection, you may be given other medications to prevent certain side effects of rituximab.

You will need frequent medical tests.

If you've ever had hepatitis B, using rituximab can cause this virus to become active or get worse. You may need frequent liver function tests while using this medicine and for several months after you stop.

If you need surgery, tell the surgeon ahead of time that you are using this medicine.

Rituximab may cause a serious brain infection that can lead to disability or death. This infection may be more likely if have used an immunosuppressant drug in the past, or if you have received rituximab with a stem cell transplant.

To make sure rituximab is safe for you, tell your doctorr if you have ever had:

• liver disease or hepatitis (or if you are a carrier of hepatitis B);

• an infection, including herpes, shingles, cytomegalovirus, chickenpox, parvovirus, West Nile virus, or hepatitis B or C;

• kidney disease;

• lung disease or a breathing disorder;

• a weak immune system (caused by disease or by using certain medicines);

• heart disease, angina (chest pain), or heart rhythm disorder; or

• if you have used rituximab in the past, or you have had a severe allergic reaction to this medicine.

You should be up-to-date on any needed immunizations before starting treatment with rituximab. Tell your doctor if you (or a child receiving rituximab) have received any vaccines within the past 4 weeks.

Do not use rituximab if you are pregnant. It could harm the unborn baby. Use effective birth control to prevent pregnancy while you are using thus medicine and for at least 12 months after your last dose.

Do not breastfeed while using this medicine, and for at least 6 months after your last dose.

Call your doctor if you miss an appointment for your rituximab injection.

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

Do not receive a "live" vaccine while using rituximab. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

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

Some side effects may occur during the injection (or within 24 hours afterward). Tell your caregiver right away if you feel itchy, dizzy, weak, light-headed, short of breath, or if you have chest pain, wheezing, sudden cough, or pounding heartbeats or fluttering in your chest.

Rituximab may cause a serious brain infection that can lead to disability or death. Call your doctor right away if you have any of the following symptoms (which may start gradually and get worse quickly):

• confusion, memory problems, or other changes in your mental state;

• weakness on one side of your body;

• vision changes; or

• problems with speech or walking.

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

Common rituximab side effects may include:

• low white and red blood cells (fever, chills, body aches, pale skin, unusual tiredness, infections);

• nausea, diarrhea;

• swelling in your hands or feet;

• headache, weakness;

• painful urination;

• muscle spasms;

• depressed mood; or

• cold symptoms such as stuffy nose, sneezing, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially:

• medicines to treat conditions such as rheumatoid arthritis, Crohn's disease, ulcerative colitis, or psoriasis - adalimumab, certolizumab, etanercept, golimumab, infliximab, leflunomide, methotrexate, sulfasalazine, tocilizumab, tofacitinib, and others.

This list is not complete. Other drugs may interact with rituximab, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.