In a controlled clinical trial conducted in 28 centers, 354 ambulatory patients with a
cimetidine-resistant duodenal or
gastric ulcer (at least six weeks of treatment at a dose of 1 g/day) confirmed by endoscopy were allocated at random to either
ranitidine or
cimetidine treatment: 166 patients received
cimetidine (1.6 g/day in 4 oral doses), and 188,
ranitidine (0.3 g/day in 2 oral doses). The two groups differed significantly with regard to sex and history of
gastrointestinal hemorrhage but not with regard to age, weight, history of peptic disease, history of perforated
ulcer, duodenal/
gastric ulcer ratio, number of smokers and alcohol consumers. The criterion of effectiveness was endoscopic healing of the
ulcer after six weeks of treatment; in case of doubt, vital staining with
methyl blue was performed. A significant difference was observed between the results of the two treatments in the duodenal group (p less than 0.05) but not in the gastric group, the healing rates being respectively 71 p. 100 and 65 p. 100 with
ranitidine, and 59 p. 100 and 44 p. 100 with
cimetidine. Twelve patients developed side-effects with a highly significant difference between the two groups: 11 patients under
cimetidine and one patient under
ranitidine (p less than 0.001). These results show the effectiveness of
ranitidine as a complementary treatment in
cimetidine-resistant
peptic ulcers of duodenal location.