Warfarin is a medication called an anticoagulant, commonly referred to as a blood thinner. The body naturally balances the ability to form clots with the ability to break them down. Warfarin, which is taken by mouth, reduces the body’s ability to form clots.
Patients who are placed on warfarin therapy are those who have certain conditions that put them at high risk of serious blood clot formation. This includes some patients with congenital heart disease. Congenital heart disease conditions where warfarin therapy is often used include:
- After having an artificial/mechanical heart valve placed
- After stenting of some blood vessels
- In certain patients who have had a Fontan procedure
- In patients who have had previous blood clotting problems
Warfarin therapy requires regular blood testing (called PT/INR) to measure the body’s clotting ability. Usually this is performed at a blood draw lab, but some insurance companies will provide for home monitoring machines. You do not want the blood to clot too easily, increasing the risk for clot formation, nor do you want the blood to not be able to clot at all, which increases the risk for a major bleeding episode. There are several factors that can affect warfarin’s effectiveness in the body, including changes in diet and the use of other medications, so it is very important to have the blood test done regularly to assess the body’s clotting ability.