Effect of Warfarin (Coumadin) Sodium Administration During Lactation on Blood Coagulation of Nursling Rats.

When a therapeutic dosage of the anticoagulant warfarin (Coumadin) sodium was fed to lactating rats, there was no effect on whole blood clotting time of the nurslings, or on their subsequent growth and reproduction. When toxic or lethal levels of warfarin sodium were fed to the mothers, clotting time was prolonged in the nurslings. This demonstrated that the anticoagulant effect could be transmitted through the milk when mothers received toxic dosages. However, at all dosages the anticoagulant effect was much less in nurslings than in mothers.