Rituximab is used to treat certain types of cancer (such as non-Hodgkin's lymphoma, chronic lymphocytic leukemia). It works by slowing or stopping the growth of cancer cells.

Some brands of rituximab are also used to treat rheumatoid arthritis and can decrease joint pain and swelling. This drug is also used to treat certain types of blood vessel disease (such as granulomatosis with polyangiitis, microscopic polyangiitis) and can decrease the swelling of the blood vessels. Rituximab is also used to treat a certain skin condition (pemphigus vulgaris). It helps to reduce the number of skin lesions.

This monograph is about the following rituximab products: rituximab, rituximab-abbs, rituximab-arrx, and rituximab-pvvr.

Read the Medication Guide provided by your pharmacist before you start using rituximab and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Your doctor should prescribe other medications (such as acetaminophen, an antihistamine, methylprednisolone) for you to take before each treatment to help reduce side effects, such as fever and chills. Carefully follow your doctor's instructions.

This medication is given by slow injection into a vein by a health care professional as directed by your doctor. The dosage and treatment schedule are based on your medical condition, body size, and response to treatment.

See also Warning section.

Nausea, vomiting, headache, dizziness, joint/muscle pain, weakness, or flushing may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.

Tell your doctor right away if you have any serious side effects, including:

• signs of stomach/intestinal blockage (such as constipation, stomach/abdominal pain)
• swelling hands/ankles/feet
• increased thirst/urination
• numbness/tingling of arms/legs

Rituximab sometimes causes side effects due to the rapid destruction of cancer cells (tumor lysis syndrome). To lower your risk, your doctor may add a medication and tell you to drink plenty of fluids. Tell your doctor right away if you have symptoms such as:

• low back/side pain (flank pain)
• signs of kidney problems (such as painful urination, pink/bloody urine, change in the amount of urine)
• muscle spasms/weakness

This medication can decrease blood cells, which can cause anemia, decrease your body's ability to fight an infection, or cause easy bruising/bleeding. Tell your doctor right away if you develop any of the following symptoms: easy bleeding/bruising, black/tarry stools, vomit that looks like coffee grounds, signs of an infection (such as sore throat that doesn't go away, fever, chills), unusual tiredness, pale skin.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using rituximab, tell your doctor or pharmacist if you are allergic to it; or to any rituximab products; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• lung disease
• heart problems (such as irregular heartbeat, previous heart attack)
• bleeding/blood disorders
• current/recent infections

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Rituximab can make you more likely to get infections or may make current infections worse. Stay away from anyone who has an infection that may easily spread (such as chickenpox, COVID-19, measles, flu). Talk to your doctor if you have been exposed to an infection or for more details.

Tell your health care professional that you are using rituximab before having any immunizations/vaccinations. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.

Older adults may be at greater risk for heart problems (such as irregular heartbeat) or lung problems while using this drug.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using rituximab. Rituximab may harm an unborn baby. Your doctor should order a pregnancy test before you start this medication. Ask about reliable forms of birth control while using this medication and for 1 year after the last dose. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.

This drug passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this drug and for at least 6 months after the last dose. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug are:

• other drugs that weaken the immune system/increase the risk of infection (such as tofacitinib, natalizumab, fingolimod)

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as complete blood count, hepatitis B virus, kidney/liver function) should be done before you start using this medication and while you are using it. Keep all medical and lab appointments.

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Not applicable. This medication is given in a hospital or clinic or doctor's office and will not be stored at home.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).