Cannabidiol (prescription) and Efavirenz, lamivudine, and tenofovir interaction
Cannabidiol (prescription) and Efavirenz, lamivudine, and tenofovir: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Cannabidiol (prescription) (Epidiolex) label · effective 2026-05-29
• Strong inducer of CYP3A4 or CYP2C19: Consider dose increase of EPIDIOLEX.
From the Efavirenz, lamivudine, and tenofovir (SYMFI) label · effective 2019-10-15
Patients who are receiving concomitant anticonvulsant medications primarily metabolized by the liver, such as phenytoin and phenobarbital, may require periodic monitoring of plasma levels [see Drug Interactions (7.5) ] .
Phenytoin Phenobarbital ↓ anticonvulsant ↓ EFV Monitor anticonvulsant plasma levels periodically because of potential for reduction in anticonvulsant and/or EFV plasma levels.
Cannabinoid Test Interaction EFV does not bind to cannabinoid receptors.
False-positive urine cannabinoid test results have been reported with some screening assays in uninfected and HIV-infected subjects receiving EFV.
Confirmation of positive screening tests for cannabinoids by a more specific method is recommended.
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.