Cannabidiol (prescription) and Clobazam interaction
Cannabidiol (prescription) and Clobazam: 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 Clobazam (SYMPAZAN) label · effective 2025-12-01
Prescribe the lowest effective dosage; avoid or minimize concomitant use of CNS depressants and other substances associated with abuse, misuse, and addiction (e.g., opioid analgesics, stimulants); and advise patients on the proper disposal of unused drug.
Cannabidiol: May increase risk of SYMPAZAN-related adverse reactions; consider dosage adjustment if this occurs ( 7.4 )
Consider a reduction in dosage of cannabidiol or clobazam if adverse reactions known to occur with SYMPAZAN are experienced.
Risk may be increased with concomitant use of other CNS depressants ( 5.4 , 5.5 )
Potentiation of Sedation from Concomitant Use with Central Nervous System Depressants Since SYMPAZAN ® has a central nervous system (CNS) depressant effect, patients or their caregivers should be cautioned against simultaneous use with other CNS depressant drugs or alcohol, and cautioned that the effects of other CNS depressant drugs or alcohol may be potentiated…
From the Cannabidiol (prescription) (Epidiolex) label · effective 2026-05-29
Risk Factors for Transaminase Elevation Concomitant Valproate and Clobazam The majority of ALT elevations in the controlled studies occurred in patients taking concomitant valproate [see Drug Interactions ( 7.3 )] .
Concomitant use of clobazam also increased the incidence of transaminase elevations, although to a lesser extent than valproate [see Drug Interactions ( 7.2 )] .
…EPIDIOLEX-treated patients with LGS or DS (10 and 20 mg/kg/day dosages), the incidence of ALT elevations greater than 3 times the ULN was 30% in patients taking both concomitant valproate and clobazam, 21% in patients taking concomitant valproate (without clobazam), 4% in patients taking concomitant clobazam (without valproate), and 3% in patients taking neither drug.
Consider discontinuation or dose adjustment of valproate or clobazam if liver enzyme elevations occur.
Consider discontinuation or dose adjustment of valproate or clobazam if ammonia level elevations occur.
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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.