References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Atazanavir (brand name Reyataz) is a protease inhibitor (PI) used in combination with other antiretroviral drugs to treat HIV-1. It was one of the first once-daily PIs and is usually taken with a low dose of ritonavir or cobicistat as a pharmacokinetic booster. While newer drug classes (integrase inhibitors) have largely replaced PIs as first-line therapy, atazanavir remains an option for specific clinical situations.
Atazanavir blocks HIV protease, an enzyme the virus needs to cut its proteins into functional pieces. Without working protease, HIV produces immature, non-infectious viral particles. This stops the virus from replicating effectively.
Dosage
- Standard dose: Atazanavir 300mg + ritonavir 100mg, once daily with food
- Alternative: Atazanavir 300mg + cobicistat 150mg (available as Evotaz)
- Must be taken with food for proper absorption
- Cannot be taken with proton pump inhibitors (omeprazole, lansoprazole) as they reduce absorption
Common Side Effects
| Side Effect | Frequency | Notes |
|---|---|---|
| Jaundice (yellowing of eyes/skin) | Common (30-40%) | Cosmetic only — caused by raised bilirubin, not liver damage |
| Nausea | Common | Usually mild, settles over time |
| Headache | Common | Settles with continued use |
| Kidney stones | Uncommon (2-5%) | Stay well hydrated to reduce risk |
| Gallstones | Uncommon | Related to raised bilirubin |
The jaundice caused by atazanavir is a well-known cosmetic issue. It’s caused by the drug inhibiting the enzyme that processes bilirubin (a breakdown product of red blood cells). It does not indicate liver damage and is reversible when the drug is stopped. However, many patients find it socially distressing, which is a common reason for switching to a different drug.
Drug Interactions
Atazanavir has significant drug interactions:
- Proton pump inhibitors: Contraindicated (omeprazole, lansoprazole). H2 blockers (ranitidine) can be used with timing restrictions
- Statins: Some statins need dose adjustment. Simvastatin is contraindicated
- Erectile dysfunction drugs: Dose reduction needed for sildenafil, tadalafil
- Hormonal contraception: May reduce effectiveness of some oral contraceptives
Always tell your HIV specialist about all medications you take, including over-the-counter drugs and supplements.
Read more: What is HIV? | Starting HIV treatment | HIV drug interactions
Frequently Asked Questions
Rarely. BHIVA guidelines now recommend integrase inhibitor-based regimens (dolutegravir, bictegravir) as first-line. Atazanavir is typically reserved for patients who cannot take integrase inhibitors or who have specific resistance patterns.
This is caused by elevated unconjugated bilirubin, a known pharmacological effect of atazanavir. It’s not harmful to your liver. If it bothers you, discuss switching to a different drug with your HIV specialist.
Antacids reduce atazanavir absorption. If needed, take antacids at least 2 hours before or 1 hour after atazanavir. Proton pump inhibitors (omeprazole) are contraindicated and should not be used at all.
Related reading
- Choosing the Right PrEP Drug: Truvada vs Descovy
- Dovato for HIV: A Two-Drug Regimen
- Triumeq for HIV: A Straightforward Guide
- Efavirenz for HIV: An Older NNRTI Still in Use
- Eviplera: How This Anti-HIV Drug Works
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
