The therapeutic use of oral anticoagulants is typically the long-term solution for the patient in terms of managing situations of thrombosis. Warfarin, a dicumarol derivative, is one of the most popular oral anticoagulants used today. While heparin is administered intravenously and acts to inhibit thrombin, warfarin is given orally, taken in pill form, and functions as a vitamin K antagonist.
In earlier discussions, it was mentioned that certain clotting factors are considered to be vitamin K dependent. They require vitamin K molecules for their action to occur. Vitamin K dependent factors include factor II, VII, IX, and X. Vitamin K dependent metabolic processes involved with these coagulation factors are inhibited by drugs such as warfarin. The chemical structure of warfarin and similar anticoagulants enables them to bind competitively with free vitamin K.
The prothrombin time (PT)/INR test is used to monitor oral anticoagulant therapy.