Drug interactions
Clozapine + Haloperidol
Severity: Major
Clozapine 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 drugs block dopamine receptors, prolong the QT interval and cause sedation, so combining them increases risk of QT prolongation, extrapyramidal effects and neuroleptic malignant syndrome. Clozapine also carries risks of seizures, myocarditis and respiratory or circulatory collapse that may be compounded by other CNS agents.
What this interaction means in plain words
Clozapine 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.
Clozapine belongs to Central Nervous System; Haloperidol belongs to Central Nervous System.
Why it happens
Additive dopamine antagonism, QTc prolongation and CNS depression.
What to do
Avoid combining unless clearly necessary; if used, obtain baseline and follow-up ECGs, check electrolytes, and monitor for sedation, rigidity and fever. Use the lowest effective doses.
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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide 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 Clozapine with Haloperidol?
MediHelp rates the interaction as major. Clozapine 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 drugs block dopamine receptors, prolong the QT interval and cause sedation, so combining them increases risk of QT prolongation, extrapyramidal effects and neuroleptic malignant syndrome. Clozapine also carries risks of seizures, myocarditis and respiratory or circulatory collapse that may be compounded by other CNS agents.
How serious is the interaction between Clozapine 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 combining unless clearly necessary; if used, obtain baseline and follow-up ECGs, check electrolytes, and monitor for sedation, rigidity and fever. Use the lowest effective doses.
What other medicines interact with Haloperidol?
MediHelp also lists interactions of Haloperidol with, for example, Dofetilide, Dronedarone, Ibutilide. The full list is on the Haloperidol page.
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