Mesalamine and olsalazine: 5-aminosalicylic acid agents for the treatment of inflammatory bowel disease.

The history, pharmacology, pharmacokinetics, clinical uses and efficacy, adverse effects, drug interactions, and dosage and administration of rectal mesalamine and oral olsalazine in the treatment of inflammatory bowel disease (IBD) are reviewed. The high incidence of toxicity associated with sulfasalazine led to the development of the nonsulfonamide 5-aminosalicylic acid products mesalamine and olsalazine. The exact mechanism of action of these agents in the treatment of IBD is unknown. In clinical trials, mesalamine was shown to be as effective as or more effective than sulfasalazine or corticosteroids in treating active ulcerative colitis, proctitis, and proctosigmoiditis. Mesalamine is effective in the maintenance of remission in patients with ulcerative colitis. Several studies have demonstrated the effectiveness of olsalazine in the treatment of active mild to moderate ulcerative colitis. Olsalazine is also effective in the maintenance of remission of ulcerative colitis. The most common adverse effect associated with mesalamine enemas is perianal irritation or trauma secondary to insertion. The most common adverse effects associated with olsalazine are dose-dependent watery diarrhea and gastrointestinal upset. The recommended dosage of the mesalamine enema for the treatment of active mild to moderate ulcerative colitis is one 4-g (60-mL) retention enema daily for three to six weeks. The dosage of mesalamine suppositories for the treatment of active ulcerative proctitis is one 500-mg suppository inserted rectally twice daily for three to six weeks. The dosage of olsalazine is 1 g daily in divided doses for the maintenance of remission of ulcerative colitis. Both rectal mesalamine and oral olsalazine provide clinicians with an effective therapeutic option for the treatment of ulcerative colitis, proctosigmoiditis, and proctitis in patients unresponsive to or intolerant of the effects of sulfasalazine or corticosteroids.