Warfarin (Coumadin® and Jantoven®) is an anticoagulant medication or “blood thinner” you take to prevent and treat blood clots that can lead to a stroke or heart attack. Warfarin is used to prevent or treat blood clots, including deep venous thrombosis or pulmonary embolism. It is also used for blood clots that may be caused by certain heart conditions, open-heart surgery, or after a heart attack. Coumadin (Warfarin Sodium) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources. Find patient medical information for Warfarin on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Warfarin is used to decrease the tendency for thrombosis, or as secondary prophylaxis (prevention of further episodes) in those individuals who have already formed a blood clot (thrombus). Prophylaxis and treatment of venous thrombosis and its extension, pulmonary embolism. (1) Prophylaxis and treatment of thromboembolic complications associated with atrial fibrillation and/or cardiac valve replacement. (1) Warfarin is an anticoagulant used to prevent heart attacks, strokes, and blood clots. Learn about side effects, interactions and indications. Take your warfarin sodium tablets exactly as prescribed to lower the chance of blood clots forming in your body (see What is warfarin sodium?). Warfarin sodium tablets are very important for your health, but it can cause serious and life-threatening bleeding problems. Warfarin may cause serious bleeding that can lead to death. Prophylaxis and treatment of thromboembolic complications associated with atrial fibrillation (AF) and/or cardiac valve replacement. Reduction in the risk of death, recurrent myocardial infarction.