How do Coumadin and Plavix work to treat blood clots?

Coumadin and Plavix are very different drugs that work in different ways. Coumadin affects the clotting factors produced in the liver and requires frequent monitoring as different patients have a variable response to Coumadin. Plavix affects platelet function, which is another part of the clotting system. It does not require frequent blood tests to monitor its effectiveness. Coumadin is generally recommended for patients who have had a blood clot in a vein of the leg for at least six months afterward. If there is a reoccurrence of a vein clot thereafter Coumadin is generally recommended lifelong. Patients with established arterial disease of their heart, legs or carotid arteries have a significant benefit from taking Plavix. There is no proven benefit to taking Plavix for vein clots.