dolutegravir + etravirine + lopinavir + ritonavir

This is a combination of four antiretroviral drugs used in the treatment of HIV infection: **dolutegravir** (an integrase strand transfer inhibitor), **etravirine** (a non-nucleoside reverse transcriptase inhibitor), **lopinavir** (a protease inhibitor), and **ritonavir** (a protease inhibitor and pharmacokinetic booster). Each component works via a different mechanism targeting HIV replication: - Dolutegravir prevents the viral DNA from integrating into the host genome. - Etravirine binds to reverse transcriptase, causing a conformational change and inhibiting enzyme activity. - Lopinavir inhibits the HIV-1 protease, thus blocking viral polyprotein cleavage and maturation. - Ritonavir primarily acts as a booster, inhibiting CYP3A4 to increase lopinavir plasma levels, but also has anti-HIV activity. This four-drug regimen is not a standard fixed-dose combination but can be co-administered for patients with HIV, especially in cases requiring regimen intensification or addressing resistance. The efficacy and safety of using all four concurrently require close clinical monitoring due to significant drug-drug interactions, particularly between etravirine, dolutegravir, and protease inhibitors.