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.
Before taking 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.
Tell your doctor 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 rituximab.
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  rituximab 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.
