In the European Union, the approved dose of atazanavir (Reyataz) is two 150mg capsules plus one 100mg ritonavir (Norvir) capsule once a day. Despite recent data demonstrating atazanavir’s effectiveness in patients who have not taken antiretroviral therapy before, atazanavir is currently only recommended for patients who have already taken at least one anti-HIV drug combination in Europe.

In the United States, the approved dose is two 200mg capsules once a day. It is available for patients who are starting HIV treatment for the first time, or who have already taken at least one anti-HIV drug regimen.

Atazanavir is the only protease inhibitor approved for once-daily dosing. Experimental doses of 300 or 400mg atazanavir plus 200mg ritonavir have been shown to improve atazanavir exposure in patients with suboptimal levels on the standard boosted dose^[1].

A dosing study in uninfected volunteers found that taking 400mg atazanavir with food increased drug concentrations by 35 to 70%, with the greatest increase in drug concentrations occurring with a light meal. Consequently, it is recommended that atazanavir be taken with food.

Atazanavir should not be used in patients with moderate to severe liver damage. In patients with mild liver damage, it should be used with caution.