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The recommended atazanavir dosage for adults who have never taken HIV medications before is 400 mg once daily. For people who have taken HIV medications in the past, the recommended dose is 300 mg of atazanavir plus 100 mg of ritonavir once daily. There are also different atazanavir dosing guidelines for people taking certain HIV medications with atazanavir (such as efavirenz or tenofovir).

Atazanavir Dosing: An Introduction

The dose of atazanavir sulfate (Reyataz®) that your healthcare provider recommends will vary, depending on a number of factors, including:
  • Other medical conditions you may have
  • Other medications you may be currently taking
  • Other HIV or AIDS medications you have taken in the past.
As always, do not adjust your dose unless your healthcare provider specifically instructs you to do so.

Atazanavir Plus Norvir

In many situations, it is recommended that atazanavir be taken with Norvir® (ritonavir), another HIV medication that is used to increase the level of atazanavir in the blood, making it more effective. Taking atazanavir without Norvir (if the combination is recommended) could result in blood levels that are too low to be effective.

Atazanavir Dosage for Adults (No Previous HIV Drug Use)

For adults that have not taken HIV drugs before ("therapy-naïve" individuals), the recommended dose is 400 mg (two atazanavir 200 mg capsules) once daily with food. However, a different dose is recommended if you take any of the following medications that can decrease the level of atazanavir in the blood:
  • Efavirenz (Sustiva®) -- atazanavir 400 mg plus Norvir 100 mg, all once daily with food (and efavirenz should be taken on an empty stomach, preferably at bedtime).
  • Tenofovir (Viread®) -- atazanavir 300 mg plus Norvir 100 mg, all once daily with food. 
  • H2 blockers, such as cimetidine (Tagamet®), famotidine (Pepcid®), nizatidine (Axid®), or ranitidine (Zantac®) -- atazanavir 300 mg plus Norvir 100 mg, all once daily with food, taken at the same time as and/or at least ten hours after the H2 blocker dose. Your healthcare provider may limit how much of the H2 blocker you may take, as well. If you cannot tolerate Norvir, the recommended dose is atazanavir 400 mg plus Norvir 100 mg once daily with food at least two hours before and at least ten hours after the H2 blocker dose. 


Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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