Ritonavir

Summary The potential for drug–drug interactions (DDIs) between direct oral anticoagulants and antiretroviral therapy (ART) is vast. Ritonavir and cobicistat are used as pharmacokinetic enhancers with either concurrent protease inhibitors or the integrase strand transfer inhibitor, elvitegravir, to optimize therapeutic concentrations by cytochrome P450 (CYP) inhibition. To date, only rivaroxaban and dabigatran have reported cases of use with ritonavir-boosted ART. Apixaban is metabolized similarly to rivaroxaban, but offers a dose reduction in the case of major DDIs. We report the successful use of reduced-dose apixaban to treat and prevent thromboembolic complications in six persons living with human immunodeficiency virus (HIV) on ritonavir- or cobicistat-boosted ART. This case series and available literature support the use of apixaban or dabigatran, depending on the boosted ART regimen