indinavir + ritonavir + lamivudine + stavudine

This drug is a **four-drug antiretroviral combination** used for the treatment of HIV-1 infection. It combines **indinavir** (a protease inhibitor), **ritonavir** (another protease inhibitor, often used as a pharmacokinetic booster), **lamivudine** (a nucleoside reverse transcriptase inhibitor, NRTI), and **stavudine** (also an NRTI). Indinavir and ritonavir inhibit the HIV-1 protease enzyme, preventing viral polyprotein cleavage required for viral maturation. Lamivudine and stavudine inhibit the HIV reverse transcriptase enzyme, blocking viral genome replication. Ritonavir also boosts indinavir plasma concentration by inhibiting CYP3A4-mediated metabolism. The combination is designed to target HIV at different stages of its replication cycle, maximizing viral suppression and reducing resistance[2][3][4]. Developed and manufactured as individual components by Merck (indinavir), AbbVie (ritonavir), and ViiV Healthcare/GSK (lamivudine), while stavudine was developed by Bristol Myers Squibb.