Introduction
As COVID-19-infected patients are immunocompromised and highly susceptible to serious opportunistic fungal infections,1 there is a need to understand and manage drug–drug interactions between antiretroviral and antifungal agents, particularly broad-spectrum voriconazole.2,3
The antiretroviral drug lopinavir/ritonavir is widely used for the treatment of HIV and is a potential candidate for the treatment of COVID-19. Ritonavir induces the hepatic activity of cytochrome P450 enzymes, namely CYP2C9, CYP2C19, and CYP1A2, but it inhibits the hepatic and intestinal activity of CYP3A4-6. Voriconazole is extensively metabolized by CYP2C19 and, to a lesser extent, by CYP2C9 and CYP3A. Therefore, concominant of voriconazole and lopinavir/ritonavir is not recommended as the AUC and Cmax of voriconazole have been shown to decrease 39% and 24% respectively, due to possible induction of CYP450 by ritonavir7. However, in this study, the voriconazole concentration was unexpectedly increased in the context of lopinavir/ritonavir coadministration in a COVID-19 patient.