Anticoagulant: An agent that is used to prevent the formation of blood clots. Anticoagulants have various uses. Some are used for the prevention or treatment of disorders characterized by abnormal blood clots and emboli. Examples of diseases and conditions that require anticoagulant treatment to reduce the risk of blood clots include heart attack, stroke, deep venous thrombosis, pulmonary embolism, and atrial fibrillation. There are different classes of anticoagulant drugs:
