Bedtime cimetidine maintenance treatment: optimum dose and effect on subsequent natural history of duodenal ulcer.

Abstract
Sixty patients, whose duodenal ulcers had healed endoscopically after 6 wk of treatment with cimetidine 1 g/day in divided doses, were treated with maintenance cimetidine 800 mg at bedtime for 6 mo. Eighteen relapsed endoscopically (30%). Of the 42 still in remission, 36 then completed a 6 mo. double-blind comparison of bedtime cimetidine 400 mg and placebo. Twelve of the 19 (63%) cimetidine-treated patients and 10 of 17 (59%) placebo-treated patients relapsed within 6 wk (NS). This high relapse rate on cimetidine contrasts with an earlier trial, in which the 6 wk relapse rate was only 2 out of 21 (10%) on bedtime cimetidine 800 mg and 16 out of 24 (66%) on placebo (P < 0.0005). Apart from the difference in the dose of cimetidine, both of the trials used the same experimental protocol during the double-blind part of the trial. In the earlier trial, however, there was no period of pretreatment with maintenance cimetidine as in the present trial. The pattern of placebo relapse was similar in both trials. Bedtime cimetidine maintenance treatment apparently does not alter the long-term natural history of duodenal ulcer once it has been withdrawn and either tolerance to cimetidine develops during long-term maintenance treatment or bedtime cimetidine maintenance treatment in the conventional dose of 400 mg is not as effective as 800 mg in prevention of endoscopic relapse, although it does reduce symptoms.