Which of the following is a common anticoagulant?

Warfarin is a commonly used anticoagulant that functions by inhibiting vitamin K-dependent clotting factors, which are crucial for the blood coagulation process. By doing so, it effectively reduces the formation of harmful blood clots and is often prescribed for conditions such as atrial fibrillation, deep vein thrombosis, and pulmonary embolism.

Maintaining a therapeutic INR (International Normalized Ratio) is essential while a patient is on warfarin, as it helps to monitor the drug's effectiveness and safety. Warfarin requires close monitoring due to its narrow therapeutic index and interactions with various foods and medications.

Aspirin, Clopidogrel, and Heparin are related to clotting but serve different roles. Aspirin and Clopidogrel are antiplatelet agents that primarily work by inhibiting platelet aggregation, while heparin is an injectable anticoagulant that works differently, often used in hospital settings for immediate anticoagulation. Thus, while the other choices have important roles in managing clotting issues, warfarin is recognized specifically as a key oral anticoagulant.