Final answer:
The anticoagulant that acts as a Vitamin K antagonist is Warfarin (Coumadin), inhibiting the synthesis of Vitamin K dependent clotting factors and preventing excessive blood clotting.
Step-by-step explanation:
The anticoagulant that acts as an antagonist to Vitamin K is Warfarin (Coumadin). Vitamin K plays a crucial role in the blood clotting process by activating certain proteins, including prothrombin, which is necessary for the formation of blood clots. Warfarin inhibits the action of Vitamin K, thereby preventing the synthesis of Vitamin K dependent clotting factors, which decreases the blood's ability to clot. It's commonly prescribed to prevent thrombosis and thromboembolism, conditions where blood clots can form and subsequently cause conditions such as strokes or heart attacks.