Atazanavir: a clear, practical guide

If you’re looking up atazanavir, you probably want straight answers — what it treats, how to take it, and what to watch for. Atazanavir (brand name Reyataz) is an HIV-1 protease inhibitor. Doctors usually prescribe it as part of combination antiretroviral therapy to keep viral load down and protect the immune system.

How atazanavir works and common dosing

Atazanavir stops HIV from maturing by blocking the protease enzyme the virus needs. That prevents new virus particles from becoming infectious. Typical adult dosing is 300 mg once daily with food when given with a booster. More commonly now it’s given as 300 mg atazanavir plus a booster: ritonavir 100 mg or cobicistat 150 mg. If given without a booster, doses and effectiveness vary, so follow your prescriber’s plan.

Take atazanavir with a meal. Food improves absorption and helps maintain steady drug levels. Don’t skip doses — missing pills can let the virus rebound and breed resistance.

Side effects, interactions and smart tips

Common side effects are nausea, headache, and stomach upset. A very typical reaction is increased bilirubin, which can cause yellowing of the skin or eyes (benign jaundice). It looks alarming but often isn’t liver damage; still, report it to your clinician. Less common problems include rash, abnormal heart conduction (PR prolongation), and liver enzyme rises. People with existing liver disease need closer monitoring.

Acid-reducing drugs change how well atazanavir absorbs. Antacids, H2 blockers, and proton pump inhibitors (PPIs) can lower atazanavir levels — sometimes dangerously so. Space antacids at least two hours before or after atazanavir, and talk to your doctor about H2 blockers or PPIs. Avoid St. John’s wort and strong enzyme inducers; they can make atazanavir ineffective.

Many drugs interact with atazanavir. It raises levels of some medicines and lowers others. Notable interactions: do not combine with simvastatin or lovastatin (risk of serious muscle damage). Some benzodiazepines and certain antiarrhythmics are risky. Always check with a pharmacist or use a reputable interaction checker before starting anything new, including herbal supplements.

Lab checks: expect baseline and periodic liver tests, bilirubin, and kidney checks if you have risk factors. Your provider may also check ECG if you’re on other meds that affect heart rhythm. If you’re pregnant or planning pregnancy, discuss options — atazanavir can be used in pregnancy but the plan may change.

Buying and safety tips: never buy antiretrovirals from unverified sources. Use a licensed pharmacy, and require a prescription. If ordering online, confirm the site is legitimate, shows contact details, and requires a prescription. Generic atazanavir sulfate is common and generally equivalent, but confirm packaging and batch numbers and ask your pharmacist if anything looks off.

If something unusual happens — worsening jaundice, severe abdominal pain, dark urine, or sudden muscle pain — contact your clinic right away. For everyday use, take atazanavir with food, avoid interacting medicines, and keep up with lab tests. Talk to your provider about questions specific to your health; they can tailor advice to your situation.