Olsalazine in active ulcerative colitis: dose finding study in Japan.

The optimal dose of olsalazine was evaluated in 37 patients with active ulcerative colitis. (16 had mild and 21 had moderate disease.) They were randomized to two groups - olsalazine, 2 g (Group A, 17 patients) and 3 g (Group B, 20 patients). The drug was administered orally at 0.5 g/day initially, then increased to 2 or 3 g/day after 1 week and continued for a further 4 weeks. Corticosteroids or immunosuppressants were not used. Group A consisted of 4 patients with total colitis, 10 with left-sided disease and 3 with proctitis, and group B of 7, 11 and 2, respectively. Efficacy was evaluated by number and consistency of stools, presence of blood and mucus, laboratory data and endoscopic examination. In group A, ten cases (59%) improved clinically, 6 were unchanged and 1 was exacerbated, and in B, the number of cases were 11 (55%), 5 and 4, respectively. The clinical improvement was confirmed by endoscopic examination in the 5th week. Diarrhoea was a common side-effect: 4 cases (24%) in group A and 9 (45%) in group B. Olsalazine, 2 g/day, was as effective as 3 g/day for clinical improvement (59%) of active ulcerative colitis. Diarrhoea was more often reported (45%) in the 3 g/day group. It was concluded that olsalazine, 2 g/day, was the optimal dose for the treatment of Japanese patients with active ulcerative colitis.