Warfarin (also known by the trade name of Coumadin®) is the oral anticoagulant used in the United States. Millions of people have safely and effectively used warfarin to prevent strokes, heart attacks, leg clots (deep venous thrombosis), lung clots (pulmonary emboli), and other disorders. However, due to its unique action on reducing blood clots, higher levels of warfarin in the blood can increase the risk of bleeding.

Warfarin requires a regular laboratory test: international normalized ratio [INR]. This blood test indirectly measures warfarin’s effect on the body’s ability to form clots. Various things can interfere with warfarin’s effect in the body, including medicines, food, and illnesses. As a result, warfarin requires careful dosing, monitoring, and follow-up. This medicine must be taken with great care. It is important to follow the rules to maximize the benefits and minimize the potential side effects.

The key to success with warfarin management is education. Patients who understand the reasons for taking warfarin and having it monitored closely are successful in their long-term therapy.