Venous Thromboembolism Due to Suspected Interaction Between Nevirapine and Rivaroxaban

Rivaroxaban is a selective, reversible inhibitor of factor Xa that is used for the prevention and treatment of venous thromboembolism (VTE) and for the prevention of stroke in patients with atrial fibrillation. Nevirapine is a non-nucleoside reverse transcriptase inhibitor that is generally given in com bination with 2 nucleoside reverse transcriptase inhibitors to suppress HIV in infected individuals. Both medications are metabolized in the liver through the cytochrome (CYP) P450 pathway. Nevirapine is also an enzyme inducer that may increase the clearance of rivaroxaban. There is a lack of information about drug interactions involving rivaroxaban after total joint replacement surgery. We report a case of VTE after total knee replacement that may have been due to an interaction between rivaroxaban and nevirapine.