abacavir + ritonavir

Abacavir + ritonavir is a combination of two antiretroviral agents used in the management of Human Immunodeficiency Virus (HIV) infection, although it is not a fixed-dose combination with its own licensing but rather co-administered as two distinct drugs within combination antiretroviral therapy regimens. - **Abacavir** is a nucleoside reverse transcriptase inhibitor (NRTI); it is a guanosine analog that is metabolized to carbovir triphosphate, which inhibits HIV-1 reverse transcriptase by acting as a chain terminator during viral DNA synthesis, preventing HIV replication[1][2][4]. - **Ritonavir** is a protease inhibitor that blocks HIV protease, an enzyme critical for viral maturation, by inhibiting cleavage of the gag-pol polyprotein, resulting in the production of immature, noninfectious virus particles[6]. Ritonavir is also frequently used as a pharmacokinetic enhancer (booster) for other protease inhibitors due to its strong inhibition of CYP3A4. This combination is considered for use as part of a larger antiretroviral regimen for HIV-1 infection but is not widely adopted as a standard dual therapy.