Figure 1.

Schematic overview of the inhibitory effects of different anticoagulants in the blood coagulation cascade. Abbreviations: AT III, antithrombin III; LMWH, low molecular weight heparin, PL, phospholipid; TF, tissue factor; VKA, vitamin K antagonists, UFH, unfractioned heparin; F###: blood coagulation factor denoted in Roman numerals. Active forms are denoted by a small “a” added to the Roman number, red lines: inhibition by anticoagulants, dotted lines: positive feedback loops by thrombin. VKA inhibit the synthesis of the coagulation factors II, VII, IX, and X by acting as a competitive inhibitor of the enzyme vitamin K epoxide reductase. LMWH and UFH bind to AT thereby increasing the ability of ATIII to inhibit thrombin up to 1000-fold. LMWH and UFH also directly inhibit FXa. UFH rather target AT III and LMWH rather target FXa. Fondaparinux, rivaroxaban, apixaban, and edoxaban directly inhibit FXa. Dabigatran directly inhibits thrombin.