The effect of pirmenol administration on the anti-coagulant activity of warfarin

The effect of administration of pirmenol, an extensively metabolized and plasma protein-bound antiarrhythmic agent, was evaluated in ten patients on chronic warfarin therapy. After a 3-week baseline period and 7 days of placebo administration, patients received 150 mg of oral pirmenol every 12 hours for 14 days. Prothrombin time was determined during the baseline and placebo periods, during pirmenol administration, and 14 days after the last pirmenol dose (washout). There was no significant difference between mean baseline, placebo, pirmenol, and washout prothrombin times. Coadministration of pirmenol does not appear to affect the anticoagulant activity of warfarin.