Concurrently Taking Duloxetine, Darunavir, and Ritonavir

Antiretroviral therapy (ART) is thestandard of care for treatment of HIV infection. For treatment-naïve pa-tients it involves the combination of at least 3 agents: 2 nucleoside reverse tran-scriptase inhibitors and either a ritonavir-boosted protease inhibitor (PI), integrase inhibitor, or nonnucleoside reverse tran-scriptase inhibitor. Two of the 4 first-line therapies for HIV and many of the alter-native regimens involve PIs boosted with ritonavir.1 PIs inhibit a number of cytochrome P450 enzymes that oxidize lipids and steroids and metabolize a mul-titude of medications. PIs specific to the patient case reported here are darunavir 800 mg/day and ritonavir 100 mg/day, both of which are strong inhibitors of CYP3A4 and modest inhibitors of CYP2D6.2,3 However, 2D6 substrates are still considered to be a cause of major drug interactions per the darunavir pre-scribing information, which showed a 70 % increase in the concentration of concurrently administered dextromethor-phan, a major CYP2D6 substrate.4 In addition to ART, the treatment of psychiatric conditions plays an integral part in providing standard of care for HIV-positive patients.1 Such medication