Dynamics of gastric acid inhibition by ranitidine in duodenal ulcer patients.

The dynamics of the inhibitory effect of ranitidine, a new H2-receptor antagonist, on histamine and pentagastrin-induced gastric secretion have been examined in duodenal ulcer patients. The inhibition by ranitidine of histamine-induced secretion was found to be competitive, whereas that of pentagastrin-induced secretion not competitive. Ranitidine was an effective inhibitor of pentagastrin-induced secretion for 8-12 h after administration. The availability of ranitidine, a powerful and long-acting inhibitor of gastric secretion, provides an opportunity of an alternative treatment from cimetidine for peptic ulcer and related diseases.