Phenobarbital and Prochlorperazine interaction

Phenobarbital and Prochlorperazine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

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

Major

CNS depressants: Closely monitor for sedation and respiratory depression.

Drug interactionsby drug classView label on DailyMed
Major

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)] .

Drug interactionsby drug classView label on DailyMed

From the Prochlorperazine (PROCHLORPERAZINE MALEATE) label · effective 2025-07-09

Major

Do not use in comatose states or in the presence of large amounts of central nervous system depressants (alcohol, barbiturates, narcotics, etc.). Do not use in pediatric surgery.

Contraindicationsby drug classView label on DailyMed
Moderate

Phenothiazines may intensify or prolong the action of central nervous system depressants (e.g., alcohol, anesthetics, narcotics).

Warningsby drug classView label on DailyMed
Moderate

Phenothiazines may lower the convulsive threshold; dosage adjustments of anticonvulsants may be necessary.

Precautionsby drug classView label on DailyMed
Minor

Potentiation of anticonvulsant effects does not occur.

Precautionsby drug classView label on DailyMed

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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.