A medication used to prevent the formation of blood clots and to maintain open blood vessels. Anticoagulants are called blood “thinners,” but they do not thin the blood, they only prevent or reduce clots, or thrombi. Anticoagulants have various uses. Some are used for the prophylaxis (prevention) or the treatment of thromboembolic disorders, such as stroke, heart attack (myocardial infarction) and deep venous thrombosis (DVT). Emboli are clots that break free, travel through the bloodstream, and lodge in a blood vessel, such as a Pulmonary embolism.