Does cranberry juice impact prothrombin time in patients on warfarin?
The blood-thinning medication warfarin acts as a vitamin K antagonist and is widely used for the primary and secondary prevention of arterial and venous thromboembolism in patients with common cardiovascular and peripheral vascular diseases. The major side effect of anticoagulant therapy is hemorrhage, and considerable effort and resources are expended in maintaining warfarin doses in a safe and effective therapeutic dose range. The therapeutic index and safety of anticoagulation therapy is assessed through measurement of the prothrombin time, which is expressed as the international normalized ratio (INR). An INR of 2.0 to 3.0 is generally considered in the therapeutic range, and the risk of bleeding increases when INR exceeds 4.0.
