Drug interactions
Haloperidol + Perphenazine
Severity: Major
Haloperidol and Perphenazine: major 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
Combining two antipsychotics adds to QT prolongation and torsades risk, and also increases extrapyramidal symptoms and sedation. Haloperidol is among the antipsychotics with higher QT liability. Perphenazine may also raise haloperidol levels through CYP2D6 inhibition.
What this interaction means in plain words
Haloperidol and Perphenazine 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.
Haloperidol belongs to Central Nervous System; Perphenazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and D2 blockade, with CYP2D6 competition or inhibition.
What to do
Avoid antipsychotic polypharmacy where possible. If unavoidable, monitor the ECG and electrolytes and watch for extrapyramidal symptoms.
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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Other interactions of Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
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 Haloperidol with Perphenazine?
MediHelp rates the interaction as major. Haloperidol and Perphenazine 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. Combining two antipsychotics adds to QT prolongation and torsades risk, and also increases extrapyramidal symptoms and sedation. Haloperidol is among the antipsychotics with higher QT liability. Perphenazine may also raise haloperidol levels through CYP2D6 inhibition.
How serious is the interaction between Haloperidol and Perphenazine?
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 antipsychotic polypharmacy where possible. If unavoidable, monitor the ECG and electrolytes and watch for extrapyramidal symptoms.
What other medicines interact with Perphenazine?
MediHelp also lists interactions of Perphenazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Perphenazine page.
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