atazanavir sulfate: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
atazanavir sulfate: clinical details
Prescribing considerations
- Initiate and supervise treatment through a clinician experienced in HIV management.
- Use as combination antiretroviral therapy; the selected product’s licence specifies ritonavir boosting.
- Base use in treatment-experienced patients on treatment history and viral resistance results.
- Food and gastric acidity materially affect bioavailability.
- Review prescription, non-prescription and herbal products before initiation and at every change.
Contraindications and cautions
- Hypersensitivity to atazanavir or an excipient.
- Severe hepatic impairment; ritonavir-boosted use is also contraindicated in moderate hepatic impairment.
- Strong CYP3A4 inducers, including rifampicin, St John’s wort and several enzyme-inducing antiseizure medicines.
- Listed narrow-therapeutic-index CYP3A4 substrates, including oral midazolam, triazolam, quetiapine, lurasidone and ergot derivatives.
- Simvastatin or lovastatin.
- Sildenafil when used for pulmonary arterial hypertension.
- Elbasvir/grazoprevir or glecaprevir/pibrentasvir.
Monitoring
- HIV viral load, adherence and resistance where clinically indicated.
- Renal function throughout treatment; assess promptly for nephrolithiasis.
- Liver function, particularly with pre-existing hepatitis or liver disease.
- Bilirubin and the clinical acceptability of jaundice or scleral icterus.
- Weight, blood glucose and lipids as part of antiretroviral care.
- Cardiac conduction or ECG where conduction disease, QT/PR risk factors or interacting medicines are present.
- During pregnancy and early postpartum, consider altered exposure and monitor maternal and neonatal bilirubin risks.
Clinical pharmacology
Atazanavir is an azapeptide HIV protease inhibitor, principally metabolised by CYP3A4. It inhibits CYP3A4 and UGT1A1; UGT1A1 inhibition explains reversible unconjugated hyperbilirubinaemia. Food improves exposure, while increased gastric pH reduces solubility and absorption.
Formulation and product differences
- The selected product is a hard capsule that should be swallowed whole.
- It contains lactose and a gelatin capsule shell.
- Alternative paediatric formulations may be available; switching formulation can change exposure and requires product-specific reassessment.
atazanavir sulfate preparations and strengths
Capsule
Route: Oral
Strengths: 150 mg, 200 mg, 300 mg
atazanavir sulfate interactions
Atazanavir and ritonavir have many clinically important interactions. A pharmacist or HIV specialist should review all medicines and supplements.
Rifampicin, carbamazepine, phenytoin, phenobarbital, apalutamide and St John’s wort
Strong CYP3A4 induction can greatly reduce atazanavir exposure, causing treatment failure and resistance; these combinations are contraindicated.
Proton-pump inhibitors, H2-receptor antagonists and antacids
Increasing stomach pH can reduce atazanavir absorption; suitability and administration timing require specialist review.
Simvastatin and lovastatin
Atazanavir can markedly increase exposure and the risk of severe muscle toxicity; use is contraindicated.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.