Drug interactions
Perphenazine + Quinidine
Severity: Major
Perphenazine and Quinidine: 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
Quinidine inhibits CYP2D6, increasing perphenazine exposure, and both can prolong the QT interval. This raises risk of arrhythmia as well as antipsychotic adverse effects.
What this interaction means in plain words
Perphenazine and Quinidine 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.
Perphenazine belongs to Central Nervous System; Quinidine belongs to Anti Parasitic.
Why it happens
Additive QT prolongation with quinidine-mediated CYP2D6 inhibition of perphenazine metabolism.
What to do
Avoid if possible; otherwise lower the perphenazine dose and monitor ECG and 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 Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
Other interactions of Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Frequently asked questions
Can I take Perphenazine with Quinidine?
MediHelp rates the interaction as major. Perphenazine and Quinidine 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. Quinidine inhibits CYP2D6, increasing perphenazine exposure, and both can prolong the QT interval. This raises risk of arrhythmia as well as antipsychotic adverse effects.
How serious is the interaction between Perphenazine and Quinidine?
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 if possible; otherwise lower the perphenazine dose and monitor ECG and extrapyramidal symptoms.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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