Atazanavir Drug Profile

What is Atazanavir?

Atazanavir is an antiretroviral medication belonging to the class of drugs known as HIV protease inhibitors. It is primarily used as part of combination therapy to treat HIV-1 infection in adults and children. This prescription medication helps suppress the replication of the HIV virus and is an important component of highly active antiretroviral therapy (HAART).

Uses

• HIV-1 treatment: Primary use as part of combination antiretroviral therapy in treatment-naive and treatment-experienced patients
• Post-exposure prophylaxis: May be used in certain cases as part of combination therapy following potential HIV exposure
• Pediatric HIV treatment: Approved for use in children and adolescents weighing at least 15 kg as part of combination therapy
• Treatment-experienced patients: Used in patients who have previously received other HIV medications, often boosted with ritonavir or cobicistat

How it works

Atazanavir works by blocking HIV protease, an enzyme that the HIV virus needs to replicate and produce mature, infectious viral particles. By inhibiting this enzyme, the drug prevents the virus from assembling properly and creating new copies of itself. This action helps reduce the viral load in the blood and allows the immune system to recover.

Side effects

Common side effects:

• Nausea and vomiting
• Diarrhea
• Headache
• Yellowing of skin or eyes (jaundice) due to elevated bilirubin
• Fatigue
• Abdominal pain
• Rash
• Dizziness

Serious side effects requiring immediate medical attention:

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• Severe liver problems or hepatitis
• Kidney stones or kidney problems
• Heart rhythm abnormalities (PR interval prolongation)
• Severe skin reactions
• Immune reconstitution inflammatory syndrome

Warnings and precautions

• Liver function: Patients with hepatitis B or C, or pre-existing liver disease require careful monitoring as atazanavir can cause liver toxicity
• Heart conditions: Use with caution in patients with pre-existing conduction system disease or those taking medications that can affect heart rhythm
• Pregnancy: Classified as pregnancy category B; should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus
• Kidney function: Monitor for kidney stones and renal impairment, especially in patients with pre-existing kidney disease
• Diabetes: May cause new onset diabetes or worsen existing diabetes mellitus

Interactions

• Proton pump inhibitors: Can significantly reduce atazanavir absorption and effectiveness; alternative acid-reducing medications may be preferred
• Rifampin: Dramatically reduces atazanavir levels and should not be used together
• Warfarin: May increase bleeding risk; requires careful monitoring of blood clotting times
• Calcium channel blockers: Atazanavir can increase levels of these heart medications, requiring dose adjustments
• Statins: Risk of increased statin levels and muscle toxicity; some statins should be avoided or used at reduced doses
• Antacids: Should be taken at least 2 hours before or 1 hour after atazanavir to avoid reducing absorption
• St. John’s wort: Can significantly decrease atazanavir levels and should be avoided
• Sildenafil and related drugs: Increased risk of side effects; dose reduction of these medications may be necessary

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Dosage

For treatment-naive adults, the typical dose is 300 mg once daily taken with ritonavir 100 mg once daily, or 400 mg once daily without ritonavir. For treatment-experienced patients, atazanavir 300 mg with ritonavir 100 mg once daily is generally recommended. All doses should be taken with food to enhance absorption. Pediatric dosing is based on body weight and should be determined by a healthcare provider experienced in treating HIV in children. Dosage adjustments may be necessary in patients with liver impairment or when used with certain other medications.

Sources: FDA DailyMed drug labels (public domain), BNF, WHO Essential Medicines List. This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting or stopping any medication.

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