The effects of intravenous famotidine on pentagastrin‐stimulated gastric secretion in man

Eight healthy male volunteers were each studied on four occasions in a 7 hour double-blind, placebo-controlled experiment. Three continuous 6 hour intravenous (i.v.) infusion rates of famotidine, calculated to achieve steady-state plasma concentrations of 10, 30 and 90 ng ml-1, were compared to placebo. Commencing at the third study hour, hourly incremental step-up i.v. infusions of pentagastrin 0.1, 0.2, 0.5, 1.0 and 2.0 micrograms kg-1. hour were administered on each of the four study days. Hourly blood samples were taken for the subsequent determination of plasma famotidine concentration. The three famotidine infusion rates inhibited basal gastric secretion. Pentagastrin-stimulated secretion was inhibited in a dose-dependent manner. The highest dose of famotidine (38.7 micrograms kg-1.hour) inhibited each infusion rate of pentagastrin-stimulated gastric secretion between 92 and 96%. The lowest dose of famotidine (4.3 micrograms kg-1.hour) inhibited pentagastrin 0.1 micrograms kg-1.hour stimulated secretion by 50% but, when stimulated with pentagastrin 2.0 micrograms kg-1.hour, gastric secretion was inhibited by only 25%. This study indicates that the intravenous preparation of famotidine is a potent inhibitor of pentagastrin-stimulated gastric acid secretion.