Towards an optimal dosage of oral-5-ASA in ulcerative colitis

This paper summarises the conclusions of the above Working Team concerning the optimal dosage of oral 5-ASA in ulcerative colitis. The presentation discusses the historical development of 5-ASA drugs, measures adopted to ensure appropriate large bowel release, and reviews experience with specific drugs (Asacol, Claversal, Pentasa and Olsalazine) in recent controlled trials using varying dosages. An 'optimal' dose for all clinical situations probably does not exist. Ulcerative colitis may present ranging in extent from proctitis to extensive colitis and may vary considerably in severity. The team see a clear need for dose range studies (in many instances not yet performed ). As regards mild to moderatively active disease, it is reasonable to expect a 5-ASA drug to perform about as well as sulphasalazine whilst avoiding sulphasalazine-related side-effects. Dosages which appear to achieve these aims are currently in the range of 1 g per day to 4.8 g per day for oral preparations (and 0.8 g per day to 2.4 g per day for maintaining patients in remission). Within this dose range there is some evidence that increasing the dose of 5-ASA in active disease up to 4.8 g per day confers increased clinical benefits. The efficacy of yet higher doses of oral 5-ASA remains an open question. In this regard the team sees an urgent need for further work on the modalities by which 5-ASA drugs are conveyed to the colon, relationship between oral intake and mucosal concentration, and studies regarding transit times, gastric emptying, and optimal timing of oral 5-ASA in relation to meals.