Sulphydryl-containing agents and the prevention of duodenal ulcer relapse.

This prospective randomized double-blind controlled study investigated whether sulphydryl-containing agents protect against the recurrence of duodenal ulceration. To this end, DL-cysteine (200 mg 4 times daily) and DL-methionine-methyl sulphonium chloride (MMSC, 500 mg 4 times daily) were administered orally. Three hundred and six consecutive smokers with previous symptomatic endoscopy-proven duodenal ulceration which had been shown endoscopically to have healed were randomized to receive for 1 year either placebo, cimetidine 400 mg at bedtime, cysteine, or MMSC. In 221 patients evaluable for efficacy, the cumulative relapse rate at 1 year was: placebo 64%, cimetidine 30%, cysteine 11% and MMSC 12%. Cimetidine was significantly effective in preventing ulcer relapse (p < 0.01), however cysteine and MMSC were more effective in this respect (p < 0.05). In the patients who relapsed, ulcer recurrence tended to occur early on placebo but to be evenly distributed over the year on active therapy. In all the study groups, the relative frequency of symptomatic to silent relapse was similar in the first and second halves of the year and was comparable among these groups. These results show that sulphydryl-containing agents significantly reduce the recurrence rate of duodenal ulceration.