Efavirenz and Efavirenz, lamivudine, and tenofovir interaction
Efavirenz and Efavirenz, lamivudine, and tenofovir: 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, lamivudine, and tenofovir (SYMFI) label · effective 2019-10-15
Lactic Acidosis and Severe Hepatomegaly with Steatosis Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs and other antiretrovirals.
• SYMFI should not be administered with other antiretroviral medications for the treatment of HIV-1 infection.
Not Recommended with Other Antiretroviral Medications SYMFI is a complete regimen for the treatment of HIV-1 infection; therefore, it should not be administered with other antiretroviral medications for treatment of HIV-1 infection.
From the Efavirenz label · effective 2024-03-31
Potential for Other Drugs to Affect Efavirenz Drugs that induce CYP3A activity (e.g., phenobarbital, rifampin, rifabutin) would be expected to increase the clearance of efavirenz resulting in lowered plasma concentrations [ see Dosage and Administration ( 2.2 ) ].
NNRTI: Other NNRTIs ↑ or ↓ efavirenz and/or NNRTI Combining two NNRTIs has not been shown to be beneficial.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
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.