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 slows down your blood’s ability to clot. Warfarin can cause major or fatal bleeding. Perform regular monitoring of international normalized ratio (INR) on all treated patients. Drugs, dietary changes, and other factors affect INR levels achieved with warfarin therapy. While COUMADIN is contraindicated during pregnancy, the potential benefits of using COUMADIN may outweigh the risks for pregnant women with mechanical heart valves at high risk of thromboembolism. Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco. Common Brand Name (s): Coumadin, Jantoven Common Generic Name (s): warfarin, warfarin Na, warfarin sodium Pronunciation: JAN-to-ven, WAR-far-in Drug Classes: anticoagulant, vitamin K antagonist Coumadin is used to prevent heart attacks, strokes, and blood clots in veins and arteries. Learn about side effects, interactions and indications. Warfarin, sold under the brand name Coumadin among others, is used as an anticoagulant medication. [11][8] It is commonly used to prevent deep vein thrombosis and pulmonary embolism, and to protect against stroke in people who have atrial fibrillation, valvular heart disease, or artificial heart valves. [11] Coumadin (warfarin) is an oral anticoagulant, a drug that inhibits the clotting of blood. Coumadin is used to treat deep vein thrombosis (DVT), pulmonary embolism, reduce the risk of stroke, and more. This handout describes warfarin, a medicine used to treat and prevent blood clots in the legs, lungs, heart, brain, and other parts of the body. All aspects of treatment with this medicine are covered from side effects to how to deal with a missed dose to how to monitor dietary intake of vitamin K. Coumadin (Warfarin Sodium) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources.