Drug interactions
Iloperidone + Perphenazine
Severity: Major
Iloperidone 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
Both are antipsychotics that prolong the QT interval, so combining them raises the risk of torsades de pointes. Additive extrapyramidal effects, sedation and neuroleptic malignant syndrome risk also occur, and perphenazine inhibits CYP2D6, which raises iloperidone exposure.
What this interaction means in plain words
Iloperidone 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.
Iloperidone belongs to Central Nervous System; Perphenazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and dopamine blockade, plus CYP2D6 inhibition by perphenazine reducing iloperidone metabolism.
What to do
Avoid the combination where possible; if unavoidable, obtain a baseline and follow-up ECG and correct potassium and magnesium. Consider reducing the iloperidone dose and monitor for extrapyramidal symptoms and sedation.
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 Iloperidone
- Iloperidone + Thioridazine Contraindicated
- Alfuzosin + Iloperidone Major
- Amiodarone + Iloperidone Major
- Amisulpride + Iloperidone Major
- Amitriptyline + Iloperidone Major
- Anagrelide + Iloperidone Major
Frequently asked questions
Can I take Iloperidone with Perphenazine?
MediHelp rates the interaction as major. Iloperidone 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. Both are antipsychotics that prolong the QT interval, so combining them raises the risk of torsades de pointes. Additive extrapyramidal effects, sedation and neuroleptic malignant syndrome risk also occur, and perphenazine inhibits CYP2D6, which raises iloperidone exposure.
How serious is the interaction between Iloperidone 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 the combination where possible; if unavoidable, obtain a baseline and follow-up ECG and correct potassium and magnesium. Consider reducing the iloperidone dose and monitor for extrapyramidal symptoms and sedation.
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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