17. Therapy with coumarins such as warfarin, Coumadin; heparin and derivative substances including low molecular weight heparin, synthetic pentasaccharide inhibitors of factor Xa such as fondaparinux and idraparinux; direct factor Xa inhibitors such as rivaroxaban and apixaban; direct thrombin inhibitors such as hirudin, lepirudin, bivalirudin, argatroban and dabigatran.