Comparative Pharmacology
Head-to-head clinical analysis: EVOTAZ versus RITONAVIR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EVOTAZ versus RITONAVIR.
EVOTAZ vs RITONAVIR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Ritonavir inhibits HIV protease, preventing cleavage of viral polyprotein precursors into functional proteins, resulting in immature, non-infectious viral particles. It also inhibits CYP3A4, enhancing pharmacokinetics of other protease inhibitors.
1 tablet (300 mg atazanavir and 150 mg cobicistat) orally once daily with food.
600 mg orally twice daily (oral solution or tablets); as part of boosted protease inhibitor regimen: 100-400 mg orally once or twice daily depending on co-administered PI.
None Documented
None Documented
Clinical Note
moderateRitonavir + Deferasirox
"The serum concentration of Deferasirox can be decreased when it is combined with Ritonavir."
Clinical Note
moderateRitonavir + Estrone sulfate
"The serum concentration of Estrone sulfate can be decreased when it is combined with Ritonavir."
Clinical Note
moderateRitonavir + Triamcinolone
"The risk or severity of adverse effects can be increased when Ritonavir is combined with Triamcinolone."
Clinical Note
moderateRitonavir + Tenofovir disoproxil
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.
Terminal elimination half-life is approximately 3-5 hours after multiple dosing; however, due to its potent CYP3A4 inhibition, the effective half-life for boosting other protease inhibitors is extended clinically.
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%.
Primarily hepatic metabolism (CYP3A4) with <3.5% excreted unchanged in urine; fecal elimination accounts for ~86% of the dose (mostly metabolites).
Category C
Category A/B
Protease Inhibitor
Protease Inhibitor
"The metabolism of Tenofovir disoproxil can be decreased when combined with Ritonavir."