Efavirenz, lamivudine, and tenofovir and Rifampin interaction
Efavirenz, lamivudine, and tenofovir and Rifampin: 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 Rifampin label · effective 2026-05-05
…Concentrations Administered with rifampin 600 mg daily, unless otherwise specified AUC = area under the time-concentration curve Drug or Drug Class and Prevention or Management Clinical Effect Antiretrovirals Prevention or Management: Concomitant use is contraindicated (see CONTRAINDICATIONS ) Atazanavir Decrease AUC by 72% Darunavir Rifampin dosage used concomitantly with…
Cabotegravir Decrease AUC by 59% Fostemsavir Decrease AUC by 82% Lenacapavir (SUNLENCA) Indicated for the treatment of human immunodeficiency virus-1 (HIV-1) infection Decrease AUC by 84% Antiretrovirals Prevention or Management: Avoid concomitant use Zidovudine Decrease AUC by 47% Indinavir Decrease AUC by 92% Efavirenz Decrease AUC by 26% Antiretrovirals Prevention…
From the Efavirenz, lamivudine, and tenofovir (SYMFI) label · effective 2019-10-15
Drugs that induce CYP3A activity (e.g., phenobarbital, rifampin, rifabutin) would be expected to increase the clearance of EFV resulting in lowered plasma concentrations.
Rifampin ↓ EFV Increase EFV total daily dose to 800 mg once daily when coadministered with rifampin to patients weighing 50 kg or more.
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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.