Pharmacotherapy of HIV: A Focus on Atazanavir/Ritonavir a Potent and Convenient Once Daily Ritonavir Boosted Protease-Inhibitor for HIV-1 Infected Adults

Atazanavir is the first azapeptide protease inhibitor. As a consequence of metabolism by the Cytochrome P450 system and excretion by drug-transporters such as P-Glycoprotein, drug interactions are considerable. They can be used to improve efficacy (ritonavir boosting) but may also cause adverse effects. Efficacy of ATV/RTV has been shown to be comparable to lopinavir/ritonavir in antiretroviral na ve patients, providing even better results in patients with high viral load. Efficacy has also been demonstrated in maintenance therapy in antiretroviral-experienced patients, and in patients with previous virologic failure, providing the best virologic response when the virus harbors less than four resistance PI mutations. The gastrointestinal tolerability and the lipid profile are better than with other PIs. The major side effect is a jaundice caused by unconjugated hyperbilirubinemia that rarely leads to discontinuation. ATV/RTV simple administration as well as tolerability may be linked with better treatment adherence. ATV/RTV is simple, potent and well tolerated. Thus it takes an important place in the treatment of HIV-infected patients, preferentially in antiretroviral-na ve or moderately pretreated populations.