How does warfarin work?
In order for your blood to form a clot, you have to have certain proteins in your blood. Normally, your liver makes these proteins and it requires vitamin K to do so. You get vitamin K from many of the foods you eat (especially green vegetables and certain oils). Warfarin reduces your liver’s ability to use vitamin K to make these blood clotting proteins, which makes it harder for your blood to clot. Vitamin K and warfarin tend to work against each other. For this reason warfarin is often referred to as a vitamin K antagonist (VKA). If your intake of vitamin K increases, you will need more warfarin to keep your blood from clotting. If your intake of vitamin K is reduced, your dose of warfarin will also have to be reduced in order to keep you from bleeding. Fortunately, both the amount of vitamin K and warfarin in your body tends to rise and fall somewhat slowly. Therefore, one way to think about this balance between warfarin and vitamin K is that it is the WEEKLY (rather than the daily
