Effect of famotidine and ranitidine on gastric secretion and emptying in the rat

The antisecretory and gastric motor effects of the new H2‐receptor antagonist famotidine (MK‐208) were compared with those of ranitidine in the rat. The Shay rat preparation (5 hr) was used for studying gastric secretion. Gastric motility was assessed by measuring gastric emptying of a liquid meal. Both compounds inhibited acid secretion in a dose‐dependent fashion. Calculated ED50 values were 0.80 and 6.84 mg·kg−1 for famotidine and ranitidine, respectively. Therefore, in this animal model, famotidine was about 9 times more potent than ranitidine. The duration of antisecretory action however, was virtually the same for both drugs. The effect of the two drugs ‐ administered at equiactive antisecretory doses ‐ on gastric emptying was different. Indeed, ranitidine significantly accelerated emptying rate, whereas famotidine was ineffective. The results of the present investigation demonstrate that famotidine is a potent and selective antisecretory compound.