Apixaban. After hip or knee replacement: LMWH remains the standard treatment.

The standard anticoagulant for prevention of venous thromboembolism in patients undergoing hip or knee replacement surgery is a low-molecular-weight heparin (LMWH) such as subcutaneous enoxaparin. Apixaban is the second oral factor Xa inhibitor, after rivaroxaban, to be approved in the European Union for use in these two situations. Three double-blind randomised trials versus enoxaparin in a total of nearly 12 000 patients failed to show that apixaban was more effective in terms of relevant endpoints: mortality, and the incidence of pulmonary embolism and symptomatic deep vein thrombosis. The incidence of bleeding did not differ between the apixaban and enoxaparin groups under the conditions of these trials. Apixaban is mainly metabolised by cytochrome P450 isoenzymes CYP 3A4 and 3A5 and also binds to P-glycoprotein, resulting in a high potential for pharmacokinetic interactions. Renal failure is a risk factor for overdose. Pharmacodynamic interactions are also likely. There is no known antidote for apixaban. In practice, LMWH remains the standard treatment.