Famotidine and ranitidine: any difference in the duration of action?

The new H2-receptor antagonist famotidine was studied to test its duration of action in comparison with ranitidine. In the conscious cat provided with gastric fistula famotidine and ranitidine, administered by bolus i.v. injection, by continuous infusion or intragastrically, had an inhibitory effect on dimaprit-induced acid secretion which lasted similarly. The only difference between the two compounds was the higher potency of famotidine. Reversibility studies carried out in the isolated gastric fundus from immature rats showed that famotidine, like ranitidine, was easily washed out even at the highest concentration tested (3 X 10(-6) M) and thus it can be considered a readily dissociable H2 antagonist in this tissue.