olsalazine

Olsalazine is an anti-inflammatory medication used in the treatment of inflammatory bowel disease, predominantly ulcerative colitis. It is a dimer of 5-aminosalicylic acid (5-ASA) linked by an azo bond. After oral administration, bacterial azo-reductases in the colon cleave the molecule to yield two molecules of 5-ASA, providing a local anti-inflammatory effect with limited systemic exposure.

Olsalazine is indicated for inducing and maintaining remission in mild to moderate ulcerative colitis and is sometimes employed when other 5-ASA formulations are not tolerated or ineffective. The usual adult dose is about 1 gram twice daily, up to 2 grams per day, with dose adjustments based on response and tolerability. It is typically avoided for acute severe colitis or in patients with significant renal impairment without medical supervision.

Compared with sulfasalazine, olsalazine does not contain a sulfapyridine moiety, so it has fewer sulfa-related adverse effects. However, it can still cause gastrointestinal side effects, especially diarrhea, as well as hypersensitivity reactions in some patients. Rare but serious adverse effects include nephrotoxicity and hepatotoxicity; patients with kidney disease or liver disease require monitoring.

Olsalazine is generally well tolerated but may be less preferred than other 5-ASA formulations due to the tendency to cause diarrhea. It is available in oral form and marketed in various countries under brand names such as Dipentum.