[Ranitidine inhibition of gastric secretion stimulated by pentagastrin. Results in 30 cases of duodenal ulcer].

The aim of this study was to investigate the effects of ranitidine on the pentagastrin stimulated gastric secretion (6 micrograms.kg.h) in 30 patients with duodenal ulcer. The drug was administered directly into the gastric lumen. Five different doses were tested: 15 mg (3 patients), 25 mg (7 patients), 50 mg (6 patients), 75 mg (5 patients), 150 mg (4 patients) and 300 mg (5 patients). Ranitidine produced a dose-dependent inhibition of maximal acid secretion (p less than 0.001). Fifty per cent inhibition was obtained with a dose of 0.342 mg.kg-1 corresponding to a dose of 22 mg for a patient weighing 65 kg. The inhibitory effect resulted from a decrease in both volumes and H+ concentrations, the influence of the later being prevalent at high dosages. A decrease in the peptic secretion has been noticed. For small dosages, it chiefly depends on the reduction of the volumes of gastric secretions, although at high dosages the concentration of pepsin was significantly reduced. These results showed that the ranitidine is a potent antisecretory drug; the dosage of 150 mg twice a day which is considered as the regular treatment for ulcer disease seems adequate. However, the authors suggest that a new controlled therapeutic trial should be started with a dosage of 150 mg per day only, divided in four unequal doses (3 X 25 mg + 75 mg). Furthermore a satisfactory control only of the nocturnal secretion, could be obtained with an unique dose of 100 (or 150) mg at bedtime.