Anatomical Therapeutic Chemical Classification System
Warfarin is a synthetic 4-Hydroxycoumarin derivative which acts by preventing the formation of active procoagulation factors II, VII, IX and X in the liver by inhibiting the vitamin K – mediated gammacarboxylation of precursor proteins. Full therapeutic activity is not achieved until circulating coagulation factors have been removed by normal catabolism. This occurs at different rates for each factor, with factor VII having the shortest half-life. Warfarin has no direct thrombolytic effect, though it may limit the extension of existing thrombi.