Atazanavir


Atazanavir, sold under the trade name Reyataz among others, is an antiretroviral medication used to treat and prevent HIV/AIDS. It is generally recommended for use with other antiretrovirals. It may be used for prevention after a needlestick injury or other potential exposure. It is taken by mouth once a day.
Common side effects include headache, nausea, yellowish skin, abdominal pain, trouble sleeping, and fever. Severe side effects include rashes such as erythema multiforme and high blood sugar. Atazanavir appears to be safe to use during pregnancy. It is of the protease inhibitor class and works by blocking HIV protease.
Atazanavir was approved for medical use in the United States in 2003. It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system. In the United States it is not available as a generic medication.

Medical uses

Atazanavir is used in the treatment of HIV. The efficacy of atazanavir has been assessed in a number of well designed trials in ART-naive and ART-experienced adults.
Atazanavir is distinguished from other PIs in that it has lesser effects on lipid profile and appears to be less likely to cause lipodystrophy. There may be some cross-resistant with other PIs. When boosted with ritonavir it is equivalent in potency to lopinavir for use in salvage therapy in people with a degree of drug resistance, although boosting with ritonavir reduces the metabolic advantages of atazanavir.

Pregnancy

Atazanavir is pregnancy category B in the United States, meaning that no evidence of harm has been found among pregnant women taking this medication. It is one of the preferred HIV medication to use in pregnant women who have not taken an HIV medication before. It was not associated with any birth defects among over 2,500 live births observed. Atazanavir resulted in a better cholesterol profile and confirmed that it is a safe option during pregnancy.

Contraindications

Atazanavir is contraindicated in those with previous hypersensitivity. Additionally, atazanavir should not be given with alfuzosin, rifampin, irinotecan, lurasidone, pimozide, triazolam, orally administered midazolam, ergot derivatives, cisapride, St. John's wort, lovastatin, simvastatin, sildenafil, indinavir, or nevirapine.

Adverse effects

Common side effects include: nausea, jaundice, rash, headache, abdominal pain, vomiting, insomnia, peripheral neurologic symptoms, dizziness, muscle pain, diarrhea, depression and fever. Bilirubin levels in the blood are normally asymptomatically raised with atazanavir, but can sometimes lead to jaundice.

Mechanism of action

Atazanavir binds to the active site HIV protease and prevents it from cleaving the pro-form of viral proteins into the working machinery of the virus. If the HIV protease enzyme does not work, the virus is not infectious, and no mature virions are made.
The azapeptide drug was designed as an analog of the peptide chain substrate that HIV protease would cleave normally into active viral proteins. More specifically, atazanavir is a structural analog of the transition state during which the bond between a phenylalanine and proline is broken. Humans do not have any enzymes that break bonds between phenylalanine and proline, so this drug will not target human enzymes.

Formulations

Atazanavir is available as a 150 mg capsule, 200 mg capsule, 300 mg capsule, and 50 mg oral powder packet. The 300 mg capsule should reduce pill burden, as one 300 mg capsule may replace two 150 mg capsules.