Heparin is a non-oral anticoagulant chemical that is often used to prevent or treat thromboembolic disorders such as stroke, myocardial infarction, peripheral artery disease, venous thrombosis, pulmonary embolism, and others. Unlike the oral anticoagulant warfarin, heparin is administered intravenously or subcutaneously. It also is distinguished from warfarin by its rapid onset of action, usually within minutes.
The anticoagulant properties of heparin derive from its ability to bind to a naturally occurring anticoagulant chemical in the body known as antithrombin (AT), enhancing its activity. AT activity, in turn, inactivates thrombin, an important molecule that causes clotting, and another naturally occurring clotting factor. By inactivating thrombin, heparin prevents formation of fibrin and inhibits activation of platelets and other clotting factors that are normally induced by thrombin.
Most adverse consequences of heparin derive from its anticoagulant...