danoprevir + efavirenz + ritonavir

Danoprevir + efavirenz + ritonavir is a combination regimen of three antiretroviral drugs, each with distinct mechanisms of action targeting HIV-1. - **Danoprevir** is a small molecule inhibitor of the NS3/4A protease of hepatitis C virus (HCV), but in rare cases it has been experimentally explored in HIV context for protease inhibition due to structural similarities. - **Efavirenz** is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that binds to and inhibits the HIV-1 reverse transcriptase enzyme, preventing viral replication. - **Ritonavir** serves two roles: it is a protease inhibitor itself targeting HIV-1 protease and it is widely used as a pharmacokinetic enhancer ("booster") of other protease inhibitors by inhibiting cytochrome P450 3A4, thereby increasing plasma concentrations of co-administered drugs. When used together, efavirenz can induce the metabolism of protease inhibitors (including danoprevir-like agents), while ritonavir inhibits their metabolism, resulting in clinically important drug–drug interactions that may affect dosing and safety. This triple combination could be considered an experimental multi-drug regimen for HIV-1 treatment, though it is not established in guidelines and not widely used in clinical practice.