Systematic review: short-term adverse effects of 5-aminosalicylic acid agents in the treatment of ulcerative colitis

Aliment Pharmacol Ther. 2004 Jan 15;19(2):179-89. doi: 10.1111/j.0269-2813.2004.01827.x.


Aim: To determine whether there is a difference in short-term adverse events in patients with ulcerative colitis treated with mesalazine, olsalazine or balsalazide.

Methods: MEDLINE was searched for articles published until 2002. Randomized trials of oral mesalazine, olsalazine or balsalazide for the treatment of active disease or the maintenance of remission were included. Outcomes of interest were the frequencies of patients experiencing adverse events and those withdrawn due to adverse events.

Results: Forty-six trials were included. One study of mesalazine vs. sulfasalazine for active colitis showed significantly fewer patients with adverse events with mesalazine. Both balsalazide vs. sulfasalazine studies for active disease showed significantly fewer withdrawals with balsalazide. One trial of balsalazide vs. sulfasalazine for maintenance showed significantly fewer patients with adverse events with balsalazide. Otherwise, no significant differences in safety outcomes were noted.

Conclusion: All three 5-aminosalicylic acid agents are safe in the short term. In mesalazine-treated patients, the frequencies of adverse events or withdrawals due to adverse events were comparable with those in placebo-treated patients and lower than those in sulfasalazine-treated patients. Overall, adverse events or withdrawals were not significantly more frequent with olsalazine than with placebo or sulfasalazine. Adverse events and study withdrawals on balsalazide were less frequent than those on sulfasalazine.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Administration, Oral
  • Aminosalicylic Acids / administration & dosage
  • Aminosalicylic Acids / adverse effects
  • Anti-Inflammatory Agents, Non-Steroidal / administration & dosage
  • Anti-Inflammatory Agents, Non-Steroidal / adverse effects*
  • Anti-Ulcer Agents / administration & dosage
  • Anti-Ulcer Agents / adverse effects
  • Colitis, Ulcerative / drug therapy*
  • Double-Blind Method
  • Humans
  • Mesalamine / administration & dosage
  • Mesalamine / adverse effects*
  • Phenylhydrazines
  • Randomized Controlled Trials as Topic


  • Aminosalicylic Acids
  • Anti-Inflammatory Agents, Non-Steroidal
  • Anti-Ulcer Agents
  • Phenylhydrazines
  • Mesalamine
  • balsalazide
  • olsalazine