Drug interactions
Chlorpromazine + Clozapine
Severity: Major
Chlorpromazine and Clozapine: major interaction.
Last updated Sources: US FDA label
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 can prolong the QT interval and cause sedation, hypotension and anticholinergic effects. Combined use increases the risk of arrhythmia and seizures.
What this interaction means in plain words
Chlorpromazine and Clozapine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Chlorpromazine belongs to Central Nervous System; Clozapine belongs to Central Nervous System.
Why it happens
Additive QT prolongation via hERG blockade, plus additive CNS and anticholinergic effects.
What to do
Avoid combining unless clearly needed. If combined, monitor ECG and electrolytes, and watch for sedation, hypotension and seizures.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Chlorpromazine with Clozapine?
MediHelp rates the interaction as major. Chlorpromazine and Clozapine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs can prolong the QT interval and cause sedation, hypotension and anticholinergic effects. Combined use increases the risk of arrhythmia and seizures.
How serious is the interaction between Chlorpromazine and Clozapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining unless clearly needed. If combined, monitor ECG and electrolytes, and watch for sedation, hypotension and seizures.
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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