Patterns of injury in mycophenolate mofetil-related colitis.

Mycophenolate mofetil (MMF) was introduced as a new immune-suppression drug in the mid-1990s. It is widely utilized in solid-organ transplantation immune-suppression regimens. Side effects include gastrointestinal (GI) toxicity in the form of nausea, vomiting, and diarrhea. Physicians tend to reduce the dose of MMF or switch their patients to an enterio-coated formula to overcome the side effects. Because GI side effects are well linked to MMF, colonoscopy is not utilized in most of the cases to investigate the diarrhea. However, Crohn's disease-like changes in the colon, erosive enterocolitis, and graft versus host disease-like colonic changes associated with the use of MMF have been reported. Colonic findings in five patients whose symptoms resolved after substituting another agent for MMF are described in the present report. Repeat colonoscopy 4 months following discontinuation of MMF showed reparative changes in one of our patients. MMF is an important drug in organ transplantation immune-suppression regimens; however, with its widespread usage, additional side effects continue to be recognized.