Ulcerative colitis is a chronic inflammatory condition primarily affecting the colon and rectum. The primary drugs used in the treatment of ulcerative colitis are aminosalicylates. They exhibit anti-inflammatory and immunosuppressive properties. They modulate inflammatory mediators and inhibit the activity of nuclear factor κB (NF-κB). Aminosalicylates also reduce inflammation by inhibiting prostaglandin and leukotriene production and decreasing neutrophil chemotaxis and superoxide generation.

Aminosalicylates have been designed to target specific gastrointestinal tract segments, ensuring effective delivery and absorption. Azo compounds such as sulfasalazine, balsalazide, and olsalazine contain 5-ASA bound by an azo bond to an inert compound or another 5-ASA molecule, allowing targeted drug delivery. At the same time, mesalamine is a unique formulation that packages 5-ASA itself in various ways to deliver it to different segments of the small or large bowel.

Clinically, aminosalicylates show efficacy in inducing and maintaining remission in ulcerative colitis. They also treat mild to moderate Crohn's disease involving the colon or distal ileum. Their potential adverse effects include hypersensitivity reactions, gastrointestinal disturbances, renal tubular damage, interstitial nephritis, and worsening of colitis. Sulfasalazine, a type of aminosalicylate, has additional side effects, including headache, skin reactions, leukopenia, and a reversible decrease in sperm count.