tenofovir + lamivudine + darunavir + ritonavir

This drug is a **combination of four antiretroviral agents**: tenofovir (a nucleotide reverse transcriptase inhibitor), lamivudine (a nucleoside reverse transcriptase inhibitor), darunavir (a protease inhibitor), and ritonavir (a protease inhibitor used as a pharmacokinetic booster). These agents act by different mechanisms to suppress replication of Human Immunodeficiency Virus Type 1 (HIV-1). This specific four-drug combination is not available as a branded, single-tablet regimen but may be prescribed as individual agents taken together for the treatment of HIV-1 infection. Each component targets key viral enzymes: tenofovir and lamivudine inhibit reverse transcriptase, preventing viral RNA from being converted into DNA, while darunavir and ritonavir inhibit the viral protease, preventing the maturation of new viral particles. Ritonavir, at low doses, acts primarily to increase darunavir plasma concentrations by inhibiting CYP3A4 metabolism. This combination may be used in treatment of HIV-1 where resistance, tolerability, or previous regimens warrant individualized therapy[1][2][4][7].