Drug interactions
Iloperidone + Quinidine
Severity: Major
Iloperidone 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 strongly inhibits CYP2D6, which increases iloperidone exposure, and both drugs prolong the QT interval. Together this markedly raises the risk of torsades de pointes.
What this interaction means in plain words
Iloperidone 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.
Iloperidone belongs to Central Nervous System; Quinidine belongs to Anti Parasitic.
Why it happens
CYP2D6 inhibition by quinidine increases iloperidone levels, combined with additive QT prolongation.
What to do
Avoid the combination. If it cannot be avoided, halve the iloperidone dose and monitor ECG and electrolytes closely.
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 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 Quinidine?
MediHelp rates the interaction as major. Iloperidone 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 strongly inhibits CYP2D6, which increases iloperidone exposure, and both drugs prolong the QT interval. Together this markedly raises the risk of torsades de pointes.
How serious is the interaction between Iloperidone 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 the combination. If it cannot be avoided, halve the iloperidone dose and monitor ECG and electrolytes closely.
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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