What type of medication is atazanavir?: A guide to this protease inhibitor for HIV

October 9, 2025 •

3 min read

First approved by the FDA in 2003, atazanavir (brand name Reyataz) is an antiretroviral medication from the protease inhibitor class used to treat human immunodeficiency virus (HIV) infection. By blocking a critical enzyme the virus needs to mature, it helps decrease the amount of HIV in the blood.

Quick Summary

Atazanavir is an antiretroviral drug and a protease inhibitor used in combination with other medications to treat HIV infection by blocking a key viral enzyme.

Key Points

Protease Inhibitor: Atazanavir is an antiretroviral medication in the protease inhibitor class, used to treat HIV-1 infection in adults and children.
Mechanism: It works by blocking the HIV protease enzyme, preventing the virus from maturing and creating new, infectious viral particles.
Dosing and Boosting: Often taken once daily, atazanavir is typically used with a boosting agent like ritonavir or cobicistat to increase its effectiveness.
Common Side Effects: Common side effects include rash, nausea, and notably, hyperbilirubinemia, which can cause a harmless yellowing of the skin and eyes.
Favorable Lipid Profile: A key advantage is its more favorable lipid profile compared to some other protease inhibitors, leading to fewer issues with high cholesterol and triglycerides.
Food is Required: For proper absorption, atazanavir must be taken with food, and its effectiveness can be significantly reduced by acid-reducing medications.
Combination Therapy: Atazanavir must always be used as part of a combination regimen with other antiretroviral drugs and is not a cure for HIV.

What type of medication is atazanavir?

Atazanavir, also known by the brand name Reyataz®, is an antiretroviral medication in the protease inhibitor (PI) class. It is used as part of combination therapy to treat human immunodeficiency virus (HIV) infection by targeting and disabling the virus's replication process. Atazanavir was among the first PIs to be taken once daily, potentially improving adherence. It is prescribed for both patients new to HIV treatment and those who have previously taken other medications.

Mechanism of action

HIV requires the protease enzyme to process viral proteins into functional components necessary for creating new infectious virus particles. Atazanavir works by blocking this enzyme, preventing the virus from maturing and thus producing non-infectious particles. This action helps control the virus's spread and supports immune system health.

Boosting with ritonavir or cobicistat

Atazanavir is often prescribed with a pharmacokinetic booster like ritonavir (Norvir®) or cobicistat (Tybost®). These boosters inhibit liver enzymes that metabolize atazanavir, increasing its concentration and duration of effect. Ritonavir-boosted atazanavir (ATV/r) uses a low dose of ritonavir for this purpose. Alternatively, Evotaz® is a fixed-dose tablet combining atazanavir and cobicistat. Boosting is frequently recommended to maintain effective drug levels and prevent resistance, especially in treatment-experienced individuals.

Forms and administration

Atazanavir is available as capsules and an oral powder. Capsules are taken once daily with food. The oral powder is for those unable to take capsules, can be mixed with food or liquid, and also requires administration with food. Taking atazanavir with food is crucial for proper absorption. Consistent adherence is vital to prevent resistance and treatment failure.

Comparing atazanavir to other protease inhibitors

Comparing boosted atazanavir (ATV/r) with lopinavir/ritonavir (LPV/r, Kaletra®) highlights differences in dosing, side effects, and metabolic impact.


Feature	Atazanavir / Ritonavir (ATV/r)	Lopinavir / Ritonavir (LPV/r)
Dosing Frequency	Once daily, simplifying regimens.	Twice daily, which may impact adherence.
Lipid Profile Impact	More favorable, with less elevation of cholesterol and triglycerides.	Higher risk of lipid abnormalities.
Gastrointestinal Side Effects	Less common, including less diarrhea and nausea.	Higher incidence of issues like diarrhea and nausea.
Bilirubin Elevation	Significantly higher risk of asymptomatic hyperbilirubinemia, causing harmless yellowing of the skin or eyes (jaundice).	Much lower incidence of bilirubin elevation.
Cardiovascular Risk	Generally considered to have a more favorable metabolic profile.	Potential for increased cardiovascular risk.

Important considerations and monitoring

Regular monitoring of liver function, kidney function, and viral load is necessary for patients taking atazanavir. Side effects can include rash, nausea, and notably, hyperbilirubinemia, leading to jaundice, which is usually not dangerous but should be monitored. Severe skin reactions are rare but possible. Atazanavir may affect heart rhythm, especially in individuals with existing heart conditions. Kidney stones and gallbladder issues are also potential side effects. Atazanavir interacts with many medications, particularly acid-reducing drugs, which can decrease its effectiveness. A healthcare provider should review all medications to identify potential interactions.

Conclusion

Atazanavir is an effective protease inhibitor used in combination HIV therapy. Its once-daily dosing and favorable lipid profile offer advantages over some older PIs like lopinavir. However, patients must be aware of potential side effects, including hyperbilirubinemia and drug interactions. Taking the medication with food, often with a booster, is essential for its success in controlling the HIV viral load. While not a cure, atazanavir is vital for managing HIV, improving patient health, and preventing transmission. For further details, consult resources like the NIH's Clinicalinfo HIV.gov site on Atazanavir.

Frequently Asked Questions

Atazanavir is sold under the brand name Reyataz®. A fixed-dose combination with the booster cobicistat is sold as Evotaz®.

Atazanavir is a protease inhibitor that binds to the active site of the HIV protease enzyme. This prevents the enzyme from cutting viral proteins into functional pieces, resulting in the production of immature, non-infectious viral particles.

Yes, atazanavir must be taken with food to ensure proper absorption and effectiveness.

Atazanavir boosting is the practice of taking atazanavir with a smaller dose of another medication, like ritonavir or cobicistat. These 'boosters' slow down the metabolism of atazanavir, increasing its concentration and extending its effect in the body.

Common side effects include nausea, vomiting, stomach pain, diarrhea, and headache. A notable side effect is hyperbilirubinemia, which can cause a yellowing of the skin and eyes.

The yellowing of the skin and eyes (jaundice) caused by atazanavir is typically due to elevated bilirubin levels (hyperbilirubinemia) and is not clinically harmful. However, any jaundice should be reported to a doctor to rule out other, more serious causes.

Taking antacids, H2 blockers, or proton pump inhibitors (PPIs) with atazanavir can reduce its effectiveness. Always consult your doctor about the best way to manage acid reflux medications while on atazanavir.

Evotaz is a fixed-dose combination tablet containing both atazanavir and the booster cobicistat. It is taken once daily with food.