Apixaban acts by directly inhibiting, in a reversible manner, free and clot-bound factor Xa to inhibit coagulation.
Apixaban acts by inhibiting coagulation, and thus prevents development of blood clots. As a result of FXa inhibition, apixaban prolongs clotting tests such as prothrombin time (PT), INR, and activated partial thromboplastin time (aPTT). Changes observed in these clotting tests at the expected therapeutic dose, however, are small, subject to a high degree of variability, and not useful in monitoring the anticoagulation effect of apixaban. The Rotachrom® Heparin chromogenic assay is not recommended for assessing the anticoagulant effect of apixaban.
Apixaban mainly undergoes o-demethylation and hydroxylation to metabolites. The major site of biotransformation is at the 3-oxopiperidinyl moiety. The main enzyme responsible for metabolism is CYP3A4/5 while CYP1A2, 2C8, 2C9, 2C19, and 2J2 are minor metabolic enzymes. There are no active metabolites and unchanged apixaban is the primary circulating entity.
Major bleeding events.