Vitamin K antagonists (coumarins), drugs used in the prevention and treatment of cardioembolism, deep vein thrombosis, and pulmonary embolism

Vitamin K antagonists are anticoagulants discovered in 1940. They are still used today in the primary and secondary prophylaxis of cardioembolism due to atrial fibrillation and deep vein thrombosis and pulmonary embolism. Warfarin, acenocoumarol, and phenprocoumon are available on the market, and they block the enzyme epoxide reductase that normally brings back the vitamin K epoxide to its reduced form, the only one capable of inducing carboxylation of the Gla-protein residues of four vitamin K-dependent coagulative factors (II, VII, IX, and X). A monitoring test such as the prothrombin time INR is required to properly adjust the dose needed to optimize the prevention of both thrombotic and bleeding episodes. In this chapter, several practical points, mainly related to our experience in the field, are considered: diet, patient education, quality of life, point-of-care monitoring, organization, and new competitors (direct oral anticoagulants thrombin and factor Xa inhibitors).