Lack of interaction between famotidine and warfarin.

In eight healthy male volunteers taking daily subtherapeutic doses of warfarin (mean daily dose = 4.0 mg), the addition of famotidine 40 mg once-a-day for seven days did not alter the prothrombin time profile, thrombotest coagulation time or total warfarin steady-state plasma concentration. Plasma peak concentration, time to peak concentration and area under curve for famotidine were not affected by the co-administration of warfarin. However the plasma half-life of famotidine was slightly, but statistically significantly longer (p less than 0.05) during maintenance treatment with warfarin (mean +/- s.e.m.: 2.58 +/- 0.14 h versus 2.96 +/- 0.16 h respectively).