Prophylactic effects of olsalazine

In a Danish multicentre trial we compared the relapse preventing effects of olsalazine and sulphasalazine in patients with ulcerative colitis over a 12 month treatment period. Two hundred and twenty seven patients (118 men) with at least two previous attacks of ulcerative colitis were randomly allocated according to a prearranged treatment schedule to olsalazine 500 mg bd or sulphasalazine 1 g bd in a double blind, double dummy fashion. One hundred and ninety seven patients completed the trial. The relapse rate after 12month in the olsalazine group was 46.9% v 42-4% in the sulphasalazine group with a 95% confidence interval for the difference in proportions of -9% to 18%. Seven per cent of the patients were withdrawn from the trial because ofadverse drug reactions and these were equally distributed between the