Adefovir and Efavirenz, lamivudine, and tenofovir interaction
Adefovir 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
Hepatitis B antiviral agents Adefovir dipivoxil Concomitant administration of adefovir dipivoxil is not recommended.
From the Adefovir (Adefovir dipivoxil) label · effective 2025-07-22
Coadministration with Other Products: Do not administer adefovir dipivoxil concurrently with VIREAD ® or other tenofovir-containing products.
Coadministration with Other Products Adefovir dipivoxil should not be used concurrently with products containing tenofovir disoproxil fumarate or tenofovir alafenamide.
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs alone or in combination with other antiretrovirals [See Warnings and Precautions (5.
Lactic Acidosis/Severe Hepatomegaly with Steatosis Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs alone or in combination with antiretrovirals.
In order to reduce the risk of resistance in patients with lamivudine resistant HBV, adefovir dipivoxil should be used in combination with lamivudine and not as adefovir dipivoxil monotherapy.
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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.