Final answer:
Warfarin works by inhibiting the liver's synthesis of prothrombin.
Step-by-step explanation:
Warfarin (Coumadin®) acts by inhibiting the synthesis of prothrombin in the liver. Prothrombin, also known as factor II, is an essential protein in the blood clotting process. Warfarin works by antagonizing the effects of vitamin K, which is crucial for the production of prothrombin and other clotting factors by the liver. The drug's effectiveness is dependent on several factors including the intake of vitamin K as well as the presence of certain enzymes produced by the liver, which can be influenced by a patient's genetic makeup. This is where pharmacogenomics can assist in tailoring warfarin doses to individual patients to prevent overdose and ensure optimal therapeutic outcomes.