Efavirenz, lamivudine, and tenofovir and Posaconazole interaction
Efavirenz, lamivudine, and tenofovir and Posaconazole: 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 Posaconazole (NOXAFIL) label · effective 2026-02-13
Prevention or Management Efavirenz Avoid concomitant use of posaconazole with efavirenz, unless the benefit outweighs the risks.
Anti-HIV Drugs that are CYP3A4 Substrates Mechanism and Clinical Effect(s) Ritonavir and atazanavir are CYP3A4 substrates and posaconazole increased plasma concentrations of these drugs [see Clinical Pharmacology (12.3) ].
Interaction Drug Interaction Rifabutin, phenytoin, efavirenz, cimetidine, esomeprazole The drug interactions with esomeprazole and metoclopramide do not apply to Noxafil tablets or Noxafil PowderMix ( 7.3 , 12.3 ).
Effects of Noxafil and Noxafil PowderMix on Other Drugs Posaconazole is a strong CYP3A4 inhibitor.
Absence of Clinically Important Interaction with Noxafil and Noxafil PowderMix Additional clinical studies demonstrated that no clinically important effects on zidovudine, lamivudine, indinavir, or caffeine were observed when administered with Noxafil 200 mg once daily; therefore, no dose adjustments are required for these drugs when coadministered with Noxafil…
From the Efavirenz, lamivudine, and tenofovir (SYMFI) label · effective 2019-10-15
Posaconazole ↓ posaconazole Avoid concomitant use unless the benefit outweighs the risks.
QT Prolonging Drugs There is limited information available on the potential for a pharmacodynamic interaction between EFV and drugs that prolong the QTc interval.
Antifungals: Itraconazole Ketoconazole ↓ itraconazole ↓ hydroxyitraconazole ↓ ketoconazole Consider alternative antifungal treatment because no dose recommendation for itraconazole or ketoconazole can be made.
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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.