Drug interactions
Chlorpromazine + Phenobarbital
Severity: Moderate
Chlorpromazine and Phenobarbital: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both drugs cause sedation, so combined use may cause marked drowsiness, hypotension and respiratory depression. Phenobarbital induces hepatic enzymes and may lower chlorpromazine exposure, and chlorpromazine may lower the seizure threshold, which matters in patients treated for epilepsy.
What this interaction means in plain words
Chlorpromazine and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive CNS depression and CYP enzyme induction by phenobarbital.
What to do
Monitor sedation and psychiatric response, and adjust the chlorpromazine dose if effect is lost. In epilepsy, watch seizure control.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
Frequently asked questions
Can I take Chlorpromazine with Phenobarbital?
MediHelp rates the interaction as moderate. Chlorpromazine and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs cause sedation, so combined use may cause marked drowsiness, hypotension and respiratory depression. Phenobarbital induces hepatic enzymes and may lower chlorpromazine exposure, and chlorpromazine may lower the seizure threshold, which matters in patients treated for epilepsy.
How serious is the interaction between Chlorpromazine and Phenobarbital?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation and psychiatric response, and adjust the chlorpromazine dose if effect is lost. In epilepsy, watch seizure control.
What other medicines interact with Chlorpromazine?
MediHelp also lists interactions of Chlorpromazine with, for example, Dofetilide, Dronedarone, Droperidol. The full list is on the Chlorpromazine page.
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