Atazanavir and Efavirenz interaction
Atazanavir and Efavirenz: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Efavirenz label · effective 2024-03-31
Treatment-experienced patients: Coadministration of efavirenz and atazanavir is not recommended.
Protease inhibitor: Lopinavir/ritonavir ↓ lopinavir * Lopinavir/ritonavir once daily dosing is not recommended when coadministered with efavirenz.
…Alteration in Dose or Regimen May Be Recommended Based on Drug Interaction Studies or Predicted Interaction Concomitant Drug Class: Drug Name Effect Clinical Comment HIV antiviral agents Protease inhibitor: Fosamprenavir Calcium ↓ amprenavir Fosamprenavir (unboosted): Appropriate doses of the combinations with respect to safety and efficacy have not been established.
Protease inhibitor: Atazanavir ↓ atazanavir * Treatment-naive patients: When coadministered with efavirenz, the recommended dose of atazanavir is 400 mg with ritonavir 100 mg (together once daily with food) and efavirenz 600 mg (once daily on an empty stomach, preferably at bedtime).
Protease inhibitor: Indinavir ↓ indinavir * The optimal dose of indinavir, when given in combination with efavirenz, is not known.
From the Atazanavir (REYATAZ) label · effective 2024-12-05
In HIV-treatment-experienced adult patients: Coadministration of REYATAZ with efavirenz is not recommended. nevirapine ↓ atazanavir ↑ nevirapine Coadministration of REYATAZ with nevirapine is contraindicated due to the potential loss of virologic response and development of resistance, as well as the potential risk for nevirapine-associated adverse reactions…
• when coadministered with drugs that are strong inducers of CYP3A due to the potential for loss of therapeutic effect and development of resistance.
• Coadministration with drugs that are strong inducers of CYP3A, due to the potential for loss of therapeutic effect and development of resistance.
Initiation of medications that inhibit or induce CYP3A may increase or decrease concentrations of REYATAZ with ritonavir, respectively.
Potential for Other Drugs to Affect REYATAZ Atazanavir is a CYP3A4 substrate; therefore, drugs that induce CYP3A4 may decrease atazanavir plasma concentrations and reduce REYATAZ’s therapeutic effect ( see Table 16 ).
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.