Clobazam and Perphenazine interaction
Clobazam and Perphenazine: 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.
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…
Prescribers should monitor patients for somnolence and sedation, particularly with concomitant use of other central nervous system depressants.
CNS Depressants and Alcohol Concomitant use of SYMPAZAN ® with other CNS depressants may increase the risk of sedation and somnolence [see Warnings and Precautions (5.4) ].
From the Perphenazine label · effective 2026-08-25
CONTRAINDICATIONS Perphenazine products are contraindicated in comatose or greatly obtunded patients and in patients receiving large doses of central nervous system depressants (barbiturates, alcohol, narcotics, analgesics, or antihistamines); in the presence of existing blood dyscrasias, bone marrow depression, or liver damage; and in patients who have shown…
If the patient is being treated with an anticonvulsant agent, increased dosage of that agent may be required when perphenazine products are used concomitantly.
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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.