Rituximab Injection: Uses, Infusion Schedule, Side Effects
Last updated September 7, 2026.
**Rituximab is a CD20-directed monoclonal antibody, a targeted biologic given by infusion in a clinic or hospital rather than taken at home.** It attaches to the CD20 protein on the surface of B cells and clears those cells from your blood, which quiets both cancerous B cells and the antibody-driven inflammation behind several autoimmune diseases. B cell counts stay low for months after a course, so infection risk continues long past the last infusion. The single most important safety point is that everyone needs hepatitis B testing before the first dose, because rituximab can reactivate a past hepatitis B infection and cause liver failure.
What does it treat?
Rituximab treats several B cell driven conditions. In cancer care it is used for CD20-positive non-Hodgkin lymphoma, including follicular lymphoma and diffuse large B cell lymphoma, where it is often combined with chemotherapy such as CHOP, and for chronic lymphocytic leukemia given with fludarabine and cyclophosphamide. In autoimmune disease it is used for moderate to severe rheumatoid arthritis in adults who did not respond well to one or more TNF blockers, always alongside methotrexate, and for granulomatosis with polyangiitis and microscopic polyangiitis, two forms of ANCA-associated vasculitis that show up as sinus and lung involvement, bloody or foamy urine, and rising creatinine. It is also approved for moderate to severe pemphigus vulgaris, a blistering disease of the skin and mouth. Rituximab is sold as Rituxan and as the biosimilars Truxima, Ruxience, and Riabni. A separate product, Rituxan Hycela, combines rituximab with hyaluronidase for a subcutaneous injection in certain lymphoma and leukemia patients after at least one full intravenous dose.
How do you take it?
Rituximab is given only as a slow intravenous infusion by trained staff, never as an IV push or bolus and never by you at home. The dose is set by condition, not by a daily pill count, so there is no daily maximum: for non-Hodgkin lymphoma it is commonly 375 mg per square meter of body surface area weekly for 4 or 8 doses or on day 1 of each chemotherapy cycle; for chronic lymphocytic leukemia it is 375 mg per square meter before cycle 1 then 500 mg per square meter on day 1 of cycles 2 through 6; for rheumatoid arthritis it is two 1,000 mg infusions two weeks apart, repeated no sooner than every 16 weeks and usually every 24 weeks; for granulomatosis with polyangiitis and microscopic polyangiitis it is 375 mg per square meter once weekly for 4 weeks, with 500 mg follow-up doses later; for pemphigus vulgaris it is 1,000 mg on day 1 and day 15, then 500 mg at month 12 and every 6 months. You will get acetaminophen and an antihistamine about 30 minutes before each infusion, plus a steroid such as methylprednisolone 100 mg IV for the autoimmune uses. The first infusion starts at 50 mg per hour and is stepped up gradually, so plan on 4 to 6 hours in the chair; later ones run faster. There are no food rules, but eat and drink normally before you come and keep drinking fluids for a few days after, since good hydration lowers the risk of tumor lysis problems. If you miss an appointment, call the infusion center to reschedule as soon as you can and do not try to double up. Tell the team right away and stop the infusion if you get chest tightness, throat swelling, wheezing, hives, dizziness, or a sudden drop in blood pressure, and call your doctor between visits for fever, a spreading rash, mouth or eye sores, dark urine, yellow skin, or new weakness, confusion, or vision loss.
Side effects to know
- Common: During and shortly after the infusion many people get chills, fever, headache, itching, flushing, a runny nose, throat irritation, or nausea, and in the weeks after a course fatigue, muscle aches, low white cell counts, and more frequent colds or sinus infections are common.
- Serious: Get help immediately and stop the infusion for signs of a severe infusion reaction or anaphylaxis such as trouble breathing, throat or tongue swelling, chest pain, or fainting, and for severe mucocutaneous reactions such as painful blisters, peeling skin, or sores in the mouth, eyes, or genitals, which can be Stevens-Johnson syndrome or toxic epidermal necrolysis. Also call your oncology or rheumatology team the same day for yellowing of the eyes, dark urine, or right upper belly pain, which can mean hepatitis B reactivation, and for new confusion, clumsiness, trouble walking, speech changes, or loss of vision, which can signal progressive multifocal leukoencephalopathy, a rare brain infection.
Who should not take it?
Rituximab should not be given if you have had a severe or anaphylactic reaction to it or to murine proteins or to any biosimilar version. Everyone needs hepatitis B screening with HBsAg and anti-HBc before the first dose, and people with active hepatitis B should not start it; carriers who do start need antiviral cover and liver monitoring during treatment and for at least 12 months after. Talk with your doctor first if you have an active or recurrent infection including tuberculosis or hepatitis C, a history of shingles, severe heart disease, angina, or arrhythmias, prior severe lung disease, low blood counts, or a weak immune system from other drugs. Live vaccines such as MMR, live nasal flu, chickenpox, and yellow fever should not be given while you are on rituximab or until B cells recover; get any needed live vaccines at least 4 weeks before the first infusion, and inactivated vaccines at least 2 weeks before. Combining rituximab with cisplatin has caused kidney failure, and other immunosuppressants such as cyclophosphamide, methotrexate, or biologics for arthritis raise infection risk. Rituximab can harm the fetus and can leave a newborn with low B cell counts, so use effective birth control during treatment and for 12 months after the last dose and tell your doctor right away if you become pregnant. Do not breastfeed during treatment or for 6 months after the last dose. Alcohol does not interact directly with rituximab, but if you are also taking methotrexate you should avoid alcohol because the combination strains the liver, and heavy drinking makes infection and liver problems more likely for anyone on this drug.
When is it an emergency?
Call 911 in the US if you collapse, cannot breathe, have swelling of the lips, tongue, or throat, develop chest pain or a very fast or irregular heartbeat, or have a seizure. Anaphylaxis and severe infusion reactions usually start within 30 to 120 minutes of the start of an infusion, most often the first one, and staff will stop the drip and treat you on the spot. Go to an emergency department for a fever of 100.4 F or higher with shaking chills, widespread blistering or peeling skin, severe belly pain with vomiting or no bowel movements, which can mean bowel blockage or perforation, or for sudden confusion, one-sided weakness, or loss of vision. Because rituximab is given by a clinician, accidental overdose at home is not a realistic risk, but if a medication mix-up happens or someone swallows or injects any drug by mistake, call Poison Control at 1-800-222-1222 for advice and call 911 if the person collapses or has trouble breathing.
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Common questions
What is the maximum dose of rituximab?
There is no daily maximum because rituximab is not a pill you take each day. The dose is per treatment and set by your condition and body size. Common label doses are 375 mg per square meter weekly for non-Hodgkin lymphoma and for vasculitis induction, 500 mg per square meter for later chronic lymphocytic leukemia cycles, and fixed 1,000 mg infusions for rheumatoid arthritis and pemphigus vulgaris. For rheumatoid arthritis the two 1,000 mg doses are given two weeks apart and repeated no sooner than every 16 weeks. Your infusion center calculates and mixes the exact dose, so there is nothing for you to measure.
Can I drink alcohol while I am on rituximab?
Alcohol does not react directly with rituximab. The bigger issue is what you are taking with it. Rituximab for rheumatoid arthritis is given with methotrexate, and alcohol plus methotrexate raises the risk of liver damage, so avoid drinking on that combination. Rituximab can also reactivate hepatitis B and stress the liver on its own, and heavy drinking makes both liver problems and infections more likely. If you drink, tell your doctor how much so your liver enzymes can be watched, and skip alcohol entirely around infusion days when you are also getting steroids and chemotherapy.
Is rituximab safe during pregnancy or breastfeeding?
Rituximab crosses the placenta in the second and third trimesters and can leave a newborn with low B cell counts and a weakened response to vaccines. The FDA label advises effective contraception during treatment and for 12 months after the last dose. If you become pregnant while on rituximab, tell your care team right away rather than stopping on your own, since some conditions are more dangerous untreated than treated. For breastfeeding, the label advises not to nurse during treatment and for 6 months after the final dose. Live vaccines for your baby, such as rotavirus, may need to be delayed if you received rituximab during pregnancy.
Do I need to fast or follow food rules before an infusion?
No. There are no food restrictions with rituximab and you do not need to fast. Eat a normal meal before you come, since infusions can run 4 to 6 hours for the first dose and low blood sugar makes reaction symptoms harder to sort out. Drink plenty of water the day before and for several days after, especially with a high tumor burden, because good hydration lowers the risk of tumor lysis syndrome. Bring snacks and take your usual medicines that morning unless your team told you to hold blood pressure pills, which they sometimes do to reduce blood pressure drops during the infusion.
What would an overdose look like, and what should I do?
Overdose at home is not a realistic risk because rituximab is only given by trained staff into a vein, and doses are calculated and checked before mixing. In trials, doses higher than the approved ones were mainly associated with more infusion reactions and lower blood counts rather than a distinct poisoning syndrome. What matters more is spotting an infusion reaction: chills, fever, throat tightness, wheezing, hives, chest pain, dizziness, or a fast heartbeat during or soon after the drip. Tell your nurse immediately so the infusion can be stopped. If any medication mix-up happens outside the clinic, call Poison Control at 1-800-222-1222, and call 911 for collapse or trouble breathing.
What drugs and vaccines interact with rituximab?
Do not get live vaccines such as MMR, varicella, live nasal flu, or yellow fever while on rituximab or until your B cells recover. Get live vaccines at least 4 weeks before your first dose and inactivated vaccines such as flu shots, COVID vaccine, and pneumococcal at least 2 weeks before, since your antibody response will be blunted afterward. Cisplatin given with rituximab has caused kidney failure and the combination is not recommended outside a trial. Other immune suppressing drugs, including methotrexate, cyclophosphamide, steroids, and TNF blockers, add to infection risk. Blood pressure medicines may be held on the morning of an infusion. Give your team a full list including over the counter products and supplements.