Diarrhea Associated with Mesalamine in a Patient with Chronic Nongranulomatous Enterocolitis

To the Editor: The use of mesalamine (5-aminosalicylic acid) for the treatment of inflammatory bowel disease seems paradoxical, since structurally similar acetylsalicylic acid and other nonsteroidal antiinflammatory drugs (NSAIDs) can cause or exacerbate intestinal inflammation and diarrhea through their effects on arachidonic acid metabolism. 1 We describe a patient with inflammatory bowel disease of the small bowel and colon who had large-volume diarrhea while fasting during treatment with mesalamine, which was associated with changes in fecal eicosanoid content that mimicked effects expected with the use of NSAIDs that relieve pain. A 57-year-old man with a 10-month history of weight loss, abdominal . . .