The therapeutic use of oral anticoagulants is typically the long-term solution for the patient in managing situations of thrombosis. Warfarin, a dicumarol derivative, is one of the most popular oral anticoagulants used today.
While heparin is administered intravenously or subcutaneously and inhibits 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 vitamin K-dependent. They require vitamin K molecules for their action to occur. The Vitamin K-dependent factors include 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) is used to monitor oral anticoagulant therapy.