darunavir + ritonavir + atazanavir

This is a combination of three antiretroviral drugs—darunavir, ritonavir, and atazanavir—all of which are protease inhibitors used in the treatment of HIV-1 infection. Darunavir and atazanavir act as direct inhibitors of the HIV-1 protease enzyme, preventing viral replication by blocking the cleavage of viral polyproteins. Ritonavir is primarily used here as a pharmacokinetic enhancer (booster), inhibiting cytochrome P450 3A (CYP3A)-mediated metabolism to increase plasma concentrations and effectiveness of other protease inhibitors like darunavir and atazanavir[5][6][9]. This triple combination is not standard clinical practice; typically, either darunavir/ritonavir or atazanavir/ritonavir are used in regimens with other antiretrovirals[2][7]. The use of all three together would be highly unusual due to overlapping mechanisms, increased risk for drug interactions, toxicity (notably hepatotoxicity and cardiac effects), and lack of evidence for added benefit.