Warfarin is an anticoagulant used to prevent heart attacks, strokes, and blood clots. Learn about side effects, interactions and indications. Crystalline warfarin sodium occurs as a white, odorless, crystalline powder that is discolored by light. It is very soluble in water, freely soluble in alcohol, and very slightly soluble in. 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). While warfarin sodium is contraindicated during pregnancy, the potential benefits of using warfarin sodium may outweigh the risks for pregnant women with mechanical heart valves at high risk of thromboembolism. 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 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. 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. 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: learn about side effects, dosage, special precautions, and more on MedlinePlus.