Mesalamine

Mesalamine, also known as 5-aminosalicylic acid (5-ASA), is an anti-inflammatory medication used to treat inflammatory bowel diseases, primarily ulcerative colitis and colitis associated with Crohn's disease. It acts locally in the colonic mucosa, with its therapeutic effect derived mainly from topical anti-inflammatory actions rather than systemic immunosuppression. The precise mechanism is not fully understood but is believed to involve modulation of inflammatory mediators, inhibition of leukotriene synthesis, and reduction of neutrophil recruitment.

Mesalamine is available in several oral and rectal formulations designed to deliver drug to specific parts of the intestine. Oral products may be delayed-release or extended-release to target the colon, while rectal forms include suppositories, foams, and enemas for distal disease. Choice depends on disease location, severity, and patient factors. Dosing is individualized.

Indications include induction and maintenance therapy for mild to moderate ulcerative colitis; treatment of proctitis and limited colitis; and, in some cases, Crohn’s disease limited to the colon or pouchitis.

Adverse effects are generally modest and include headache, nausea, abdominal pain, and diarrhea. Less common may be rash or fever. Rare but serious adverse effects include pancreatitis and kidney-related problems such as interstitial nephritis; risk is higher with sulfasalazine (which includes a sulfapyridine moiety) than with many modern mesalamine formulations that do not contain sulfapyridine. Caution in kidney disease or severe liver impairment. Pregnancy is generally considered compatible with appropriate medical supervision. Interactions are limited; it is advised to monitor concurrent nephrotoxic drugs and NSAIDs for potential added GI irritation.