Rituximab and ulcerative colitis: what to know

Ulcerative colitis is an inflammatory condition affecting the lining of the large bowel. Its activity can cause bloody diarrhoea, urgency, cramps and abdominal pain. Rituximab changes immune-cell activity and is used for selected immune-mediated illnesses, but it is not a standard medicine for controlling ulcerative colitis. Symptoms after an infusion could reflect a flare, an infection, a medicine effect or another bowel problem; the timing alone cannot identify the cause. Learn more about [Ulcerative Colitis](/conditions/ulcerative-colitis/) before discussing the possibilities with your clinician.

Contact the clinician managing your bowel condition if you develop new [Diarrhoea](/symptoms/diarrhoea/), blood or mucus in stool, urgency or [Abdominal Pain](/symptoms/abdominal-pain/). Keep a record of stool changes, fever, weight change, recent antibiotics, infusion dates and current medicines. The assessment may include an examination, stool tests, blood tests and review of your existing ulcerative colitis plan. Do not start leftover steroids, anti-diarrhoeal medicine or antibiotics without advice, particularly if infection is possible. A [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) can help coordinate assessment.

Seek urgent help for heavy rectal bleeding, severe or rapidly worsening abdominal pain, a swollen abdomen, repeated vomiting, inability to drink, fainting, confusion or a high fever. Prompt assessment is also needed when diarrhoea is frequent, symptoms are disrupting hydration, or you feel acutely unwell after rituximab. Do not assume these signs are an ordinary flare.

Is rituximab relevant to my bowel symptoms? Could this be a flare, infection or another medicine effect? Which tests should I have? What should I do with my usual ulcerative colitis medicines while I am being assessed?