Comparative Pharmacology
Head-to-head clinical analysis: ATAZANAVIR SULFATE RITONAVIR versus EVOTAZ.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ATAZANAVIR SULFATE RITONAVIR versus EVOTAZ.
ATAZANAVIR SULFATE; RITONAVIR vs EVOTAZ
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Atazanavir is an azapeptide HIV-1 protease inhibitor that inhibits the virus-specific processing of viral Gag and Gag-Pol polyproteins in HIV-1 infected cells, preventing formation of mature virions. Ritonavir is an HIV protease inhibitor that also inhibits CYP3A, boosting atazanavir levels.
EVOTAZ is a fixed-dose combination of atazanavir, an HIV-1 protease inhibitor, and cobicistat, a CYP3A inhibitor. Atazanavir inhibits HIV-1 protease, preventing cleavage of viral polyproteins and resulting in immature, non-infectious virions. Cobicistat increases systemic exposure of atazanavir by inhibiting CYP3A-mediated metabolism.
Atazanavir 300 mg with ritonavir 100 mg orally once daily with food.
1 tablet (300 mg atazanavir and 150 mg cobicistat) orally once daily with food.
None Documented
None Documented
Atazanavir: ~6.5-7 hours (when boosted with ritonavir). Ritonavir: ~3-5 hours. Clinical context: Atazanavir requires ritonavir boosting to achieve therapeutic trough concentrations; once-daily dosing maintains efficacy.
Cobicistat: terminal half-life approximately 3–4 hours; atazanavir: terminal half-life approximately 7 hours (range 5–12 hours) at steady state when boosted with cobicistat. The short half-life of cobicistat necessitates once-daily dosing with atazanavir to maintain therapeutic concentrations.
Biliary/fecal (major route): atazanavir 79% as unchanged drug, 13% as metabolites; ritonavir 86.4% as metabolites, 3.5% unchanged. Renal: atazanavir 7% (20% as unchanged); ritonavir 11.3% (3.5% unchanged).
Cobicistat: primarily hepatic metabolism (CYP3A4) and biliary/fecal excretion; <7% excreted unchanged renally. Atazanavir: primarily biliary/fecal excretion as unchanged drug and metabolites (79–88%); renal excretion accounts for <7%.
Category A/B
Category C
Protease Inhibitor
Protease Inhibitor