Famotidine: a potent inhibitor of gastric acid secretion

In a double-blind study, 10 healthy volunteers received the H2-antagonist famotidine [L-643341; MK-208; YM-11170; Yamanouchi] in doses of 5,10 and 20mg, cimetidine 300mg and placebo. Each test dose (given at least a week apart) was administered after an overnight fast and pentagastrin 6 ltg/kg was given subcutaneously 1.5 hours later. The gastric acid and pepsin output was determined 1 - 1.5 hours (basal) and 1.5 - 2.5 hours after drug administration.

Both H2-antagonists produced a significant reduction in basal and pentagastrin-stimulated acid output compared with placebo and the reduction caused by famotidine 20mg was still significant 11-12 hours after the drug was given. Further, after pentagastrin administration, famotidine 20mg produced the greatest reduction (90% of control) in acid output and cimetidine 300mg (55%) the smallest reduction . The reductions produced by famotidine 5mg (60%) and 10mg (70%) were approximately equal to those of cimetidine 300mg and famotidine 20mg, respectively. Both cimetidine and famotidine also caused similar reductions in basal and pentagastrin-stimulated pepsin output.

An analysis of the parietal and non-parietal components of gastric secretion showed that H2-

antagonists 'primarily affect parietal cell secretion'. The volume of parietal secretion fell as acid output was reduced but non-parietal secretion was similar in the active treatment and placebo groups. The authors concluded ' ••. that famotidlne was a potent inhibitor of gastric acid secretion' and 'the possibility of prolonged acid suppression suggests that it may be possible to administer it as infrequently as once a day'. Lacey Smith. J.; Gamal. M.A.; Chremos. A.N. and Graham. D. Y.: Digestive Diseases and Sciences 30: 308·312 (Apr 1985)

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