Oral delayed-release mesalazine is an enteric-coated formulation which releases mesalazine in the terminal ileum and colon. Up to 74% of patients with mild to moderately active ulcerative colitis experience endoscopic or symptomatic improvement (including remission) or both when treated with oral delayed-release mesalazine 2.4 to 4.8 g/day. There is a trend towards a better response in patients receiving higher daily dosages of oral delayed-release mesalazine, especially in patients with active distal disease. In patients with left-sided ulcerative colitis, oral balsalazide 6.75 g/day appears to be more effective than oral delayed-release mesalazine 2.4 g/day, but a higher dosage of oral delayed-release mesalazine 4.8 g/day may provide additional benefit in these patients. Oral delayed-release mesalazine 0.8 to 4.4 g/day appears to be as effective as sulfasalazine 2 to 4 g/day, prolonged-release mesalazine 1.5 g/day or balsalazide 3 g/day in maintaining remission in patients with ulcerative colitis. The optimal dosage of oral delayed-release mesalazine for the maintenance of remission is unclear. However, oral delayed-release mesalazine 1.6 g/day with rectal mesalazine 4g, administered twice weekly, was more effective than oral drug alone in maintaining remission in patients at high risk of relapse. In patients with left-sided or distal disease oral olsalazine 1 g/day appeared to be superior to oral delayed-release mesalazine 1.2 g/day for maintenance of symptomatic remission. Limited data in patients with Crohn's disease have shown oral delayed-release mesalazine 0.4 to 4.8 g/day to be an effective therapy for active disease (remission in up to 45% of patients) and for quiescent disease (relapse in 34% of recipients over a duration of up to 12 months). Preliminary data indicate that oral delayed-release mesalazine 2.4 g/day is effective in preventing postoperative recurrence of Crohn's disease. Oral delayed-release mesalazine is effective and well tolerated in sulfasalazine-intolerant patients with ulcerative colitis or Crohn's disease.
Conclusions: Oral delayed-release mesalazine is effective in patients with mild to moderately active or quiescent ulcerative colitis. Available data suggest that patients with left-sided or distal ulcerative colitis are likely to require higher daily dosages of oral delayed-release mesalazine or supplementation with rectal mesalazine. Oral delayed-release mesalazine also appears to be effective in active and quiescent Crohn's disease. The drug is well tolerated and it appears to be effective in sulfasalazine-intolerant patients.