ATC Group: B01AA Vitamin K antagonists

Acenocoumarol is a derivative of coumarin used as anticoagulant because acts as an antagonist of vitamin K. Vitamin K antagonists produce their anticoagulant effect by inhibition of the vitamin K-epoxide-reductase with a subsequent reduction of the gammacarboxylation of certain glutamic acid molecules which are located at several sites near the terminal end both of coagulation factors II (prothrombin), VII, IX, and X and of protein C or its cofactor protein S.

Phenindione is a synthetic anticoagulant which acts by interfering with the formation of certain clotting factors.

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.