Products
ATAZOR-R
Pharmacotherapeutic group
Combination drug, antiviral for the treatment of HIV infectionsInternational name
Atazanavir + RitonavirDosage form
TabletsAntiviral drug, fixed-dose combination.
Atazanavir is an azapeptide HIV-1 protease inhibitor. It selectively blocks the virus-specific processing of viral Gag-Pol proteins in HIV-infected cells, thus preventing formation of mature virions and infection of other cells. During the treatment, a resistance to the drug (drug-specific resistance) or to both atazanavir and other HIV protease inhibitors (cross resistance) may emerge in some patients.
Ritonavir is an oral HIV 1 and 2 aspartyl protease inhibitor and a potent peptidomimetic. Inhibition of HIV protease renders the enzyme incapable of processing the Gag-Pol polyprotein precursor which leads to production of non-infectious immature HIV particles. Ritonavir is selective in its affinity for HIV protease and has little inhibitory activity against human aspartyl proteases.
It is used as a pharmacokinetic enhancer due to its potent inhibitory effect on metabolism mediated by CYP3A4 isoenzymes. The degree of enhancement is related to the metabolic pathway of the co-administered protease inhibitor and the impact of the co-administered protease inhibitor on the metabolism of ritonavir. Maximal inhibition of metabolism of the co-administered protease inhibitor is generally achieved with ritonavir doses of 100 mg daily to 200 mg twice daily, and is dependent on the co-administered protease inhibitor.