The effect of bumetanide on the serum disappearance of warfarin sodium.

Ten normal subjects were given 0.8 mg/kg warfarin orally, and daily blood samples were taken for one week to test for prothrombin activity and warfarin levels, the latter determined specifically by a high-performance liquid chromatography method. Bumetanide at a dose of 1 mg/day was then administered for 14 days. A second dose of warfarin was given on the eighth day of bumetanide administration. The curves showing disappearance of warfarin from the blood were identical before and during bumetanide administration. The prothrombin times were similar in both studies. It is concluded that bumetanide does not influence anticoagulant activity or its duration when warfarin and bumetanide are given simultaneously.