Warfarin: Mechanism and Risks

Warfarin is an oral anticoagulant that prevents blood clots by inhibiting vitamin K-dependent clotting factors two, seven, nine, and ten. It is used for atrial fibrillation, deep vein thrombosis, pulmonary embolism, and mechanical heart valve patients. The major risk is bleeding, which can be life-threatening. Warfarin has a narrow therapeutic window monitored by the International Normalized Ratio, or INR, with a target of 2.0 to 3.0 for most conditions. Warfarin interacts with many foods containing vitamin K, such as leafy green vegetables, and numerous medications.