Clobazam and Phenytoin interaction

Clobazam and Phenytoin: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.

What the FDA labels say

From the Clobazam (SYMPAZAN) label · effective 2025-12-01

Moderate

Risk may be increased with concomitant use of other CNS depressants ( 5.4 , 5.5 )

Warnings and precautionsby drug classView label on DailyMed
Moderate

Prescribers should monitor patients for somnolence and sedation, particularly with concomitant use of other central nervous system depressants.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Therefore, caution patients or their caregivers against simultaneous use with other CNS depressant drugs or alcohol, and caution that the effects of other CNS depressant drugs or alcohol may be potentiated [see Warnings and Precautions (5.4) ].

Drug interactionsby drug classView label on DailyMed

From the Phenytoin label · effective 2024-12-24

Moderate

Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Asian ancestry taking other antiepileptic drugs associated with SJS/TEN, including phenytoin.

Warnings and precautionsby drug classView label on DailyMed
Moderate

…defects), and abnormalities characteristic of fetal hydantoin syndrome, including dysmorphic skull and facial features, nail and digit hypoplasia, growth abnormalities (including microcephaly), and cognitive deficits, have been reported among children born to epileptic women who took phenytoin alone or in combination with other antiepileptic drugs during pregnancy.

Warnings and precautionsby drug classView label on DailyMed

Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.

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Not 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.