Drug interactions
Chlorpromazine + Haloperidol
Severity: Major
Chlorpromazine and Haloperidol: major interaction.
Last updated Sources: UK SmPC
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 antipsychotics can prolong the QT interval, and combined use increases the risk of torsades de pointes. Additive extrapyramidal, sedative and hypotensive effects can also occur.
What this interaction means in plain words
Chlorpromazine and Haloperidol 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; Haloperidol belongs to Central Nervous System.
Why it happens
Additive blockade of cardiac repolarizing potassium channels and additive D2 antagonism; chlorpromazine may also inhibit CYP2D6 and raise haloperidol levels.
What to do
Avoid the combination where possible and use a single antipsychotic. If both are needed, monitor ECG and correct potassium and magnesium.
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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Frequently asked questions
Can I take Chlorpromazine with Haloperidol?
MediHelp rates the interaction as major. Chlorpromazine and Haloperidol 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 antipsychotics can prolong the QT interval, and combined use increases the risk of torsades de pointes. Additive extrapyramidal, sedative and hypotensive effects can also occur.
How serious is the interaction between Chlorpromazine and Haloperidol?
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 the combination where possible and use a single antipsychotic. If both are needed, monitor ECG and correct potassium and magnesium.
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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