Review article: aminosalicylates in inflammatory bowel disease

Aminosalicylate therapy for ulcerative colitis remains a foundational strategy for the induction and maintenance of remission for mild to moderate disease. Although it seems clear that topical mesalazine (mesalamine) is the most efficacious approach to distal ulcerative colitis, recent trials with orally delivered azo conjugates suggest that there may be an advantage over pH-released mesalazine as a first-line approach to active disease. No such comparisons are available for azo products and the prolonged-release formulation, Pentasa. However, recent meta-analyses have demonstrated that, although there is little difference in systemic exposure between marketed products, luminal concentrations may vary. In maintenance therapy, aminosalicylates remain the standard approach after aminosalicylate-induced remission. A number of gaps remain in the evidence base with regard to the optimal dosing of oral mesalazine as a maintenance agent, whether oral mesalazine can maintain remissions after rectal mesalazine induction, and the dose-response and efficacy of aminosalicylates after steroid- or ciclosporin-induced remissions. Although aminosalicylates have been advocated for several decades in Crohn's disease, a number of controversies have evolved since the original trials with sulfasalazine in active Crohn's disease. The original trials demonstrated benefits for sulfasalazine in colonic involvement, but controlled trial evidence for the role of sulfasalazine as maintenance therapy has not been as firmly established. In addition, although oral mesalazine has been demonstrated in controlled trials to be superior to placebo in mild to moderate disease, it is less efficacious than corticosteroids at inducing remissions. The maintenance benefits of mesalazine appear to be limited to patients 'induced into remission' with mesalazine and in some post-operative settings.