atazanavir + ritonavir + lopinavir

Atazanavir, ritonavir, and lopinavir are antiretroviral drugs used in the treatment of HIV infection. Atazanavir and lopinavir are both protease inhibitors that prevent the cleavage of viral polyproteins necessary for HIV maturation. Ritonavir is also a protease inhibitor but is primarily used here as a pharmacokinetic enhancer ("booster") due to its potent inhibition of cytochrome P450 3A4 (CYP3A4), which increases plasma concentrations of co-administered protease inhibitors like atazanavir and lopinavir[6][3]. Lopinavir is only available clinically in combination with ritonavir because it has poor oral bioavailability on its own[6]. The combination may be considered in select clinical scenarios for patients with HIV infection; however, use together requires careful monitoring due to potential drug-drug interactions and overlapping toxicities such as QT prolongation[8]. Atazanavir/ritonavir has been shown to have better viral suppression with lower risk of lipid abnormalities compared to lopinavir/ritonavir but carries a higher risk for hyperbilirubinemia[1].

Brand names

Kaletra (for lopinavir/ritonavir)Reyataz (for atazanavir, when marketed alone)

Other names

ATV/r (atazanavir/ritonavir)LPV/r (lopinavir/ritonavir)