Cannabidiol (prescription) and Phenobarbital interaction
Cannabidiol (prescription) and Phenobarbital: 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 Phenobarbital (SEZABY) label · effective 2025-12-23
CNS depressants: Closely monitor for sedation and respiratory depression.
CNS Depressants Closely monitor for signs of sedation and respiratory depression with concomitant use of SEZABY with other CNS depressants, including opioids [see Warnings and Precautions (5.1)] .
From the Cannabidiol (prescription) (Epidiolex) label · effective 2026-05-29
Other CNS depressants, including alcohol, could potentiate the somnolence and sedation effect of EPIDIOLEX.
• Strong inducer of CYP3A4 or CYP2C19: Consider dose increase of EPIDIOLEX.
Effect of EPIDIOLEX on Other Drugs Antiepileptic Drugs Clobazam Concomitant use of EPIDIOLEX with clobazam increases plasma concentrations of N‑desmethylclobazam, the active metabolite of clobazam [see Clinical Pharmacology ( 12.3 )], which may increase the risk of clobazam-related adverse reactions [see Adverse Reactions ( 6.1 ) and Warnings and Precautions…
CNS Depressants and Alcohol Concomitant use of EPIDIOLEX with other CNS depressants (including alcohol) may increase the risk of sedation and somnolence [see Warnings and Precautions ( 5.2 )] .
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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.