Rivaroxaban is an orally-bioavailable, oxazolidinone-based inhibitor (Ki = 0.4 nM) of factor Xa, the factor in the blood coagulation pathway leading to thrombin generation and clot formation. [1] It is approved for both deep vein thrombosis and pulmonary embolism. It is >10000-fold selective for fXa over other biologically relevant serine proteases. Rivaroxaban inhibits prothrombinase-bound (IC50 = 2.1 nM, and clot-associated factor Xa (IC50 = 75 nM) in a dose-dependent manner. [1]

In vivo, Rivaroxaban inhibits endogenous fXa more potently in human and rabbit plasma (IC50 = 21 nM) than in rat plasma (IC50 = 290 nM). [2] In human plasma, PT and aPTT were doubled at 0.23 and 0.69 uM, respectively.