Adverse effects of sulfasalazine and treatment of ulcerative colitis with mesalazine

We investigated the adverse effects of sulfasalazine in the treatment of inflammatory bowel disease in Japan. In our first survey, adverse effects were observed in 52 out of 751 patients with ulcerative colitis (6.9%) and in 8 out of 221 patients with Crohn's disease (3.6%); i.e., such effects were observed in 60 out of 972 patients with inflammatory bowel disease. In our second survey, we examined 94 adverse reactions in 64 patients with ulcerative colitis. The main adverse reactions were exanthema, fever, nausea and vomiting, angioedema, and liver damage, in decreasing order of frequency; these reactions accounted for about 80% of the adverse reactions. Most of the reactions (62%) occurred within 1 month after the beginning of sulfasalazine intake. Mesalazine is thought to effectively release the 5-ASA molecule in the colon and has already proven of value in patients with mild active ulcerative colitis. We evaluated the effect of mesalazine in patients intolerant to sulfasalazine. Effectiveness was observed in 14 out of 18 patients with active ulcerative colitis (78%) and in 3 out of 3 patients in the quiescent state. These results suggest that mesalazine is effective for the treatment of patients with ulcerative colitis who are intolerant to sulfasalazine; this drug could be a gleam of hope to those patients.