What causes warfarin induced necrosis?
Warfarin is a widely used anticoagulant or blood-thinner. It works by inactivating vitamin K-dependent clotting factors II, VII, IX and X. At the same time, Vitamin K dependent proteins C and S are inactivated – these are natural anticoagulants. Half the activated Protein C disappears within 6 hours (its half-life). So, Protein C runs out during the first few days of warfarin therapy, before Factor X and II disappear, which have half-lives of 2-5 days. In some circumstances this leads to excessive clotting. Why the skin necrosis happens in the areas of fat abundance is unclear; possibly these areas are more susceptible because of reduced blood supply.
