Drug interactions
Quinidine + Risperidone
Severity: Major
Quinidine and Risperidone: 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 and P-gp, which raises concentrations of risperidone's parent compound and may cause more extrapyramidal effects, sedation and hypotension. Both drugs also prolong the QT interval, adding to the risk of torsades de pointes.
What this interaction means in plain words
Quinidine and Risperidone 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 belongs to Anti Parasitic; Risperidone belongs to Central Nervous System.
Why it happens
CYP2D6 and P-gp inhibition by quinidine increases risperidone exposure, combined with additive QT prolongation.
What to do
Avoid the combination where possible. If used, start risperidone at a low dose, titrate cautiously, and monitor ECG, electrolytes 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 Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone Major
Frequently asked questions
Can I take Quinidine with Risperidone?
MediHelp rates the interaction as major. Quinidine and Risperidone 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 and P-gp, which raises concentrations of risperidone's parent compound and may cause more extrapyramidal effects, sedation and hypotension. Both drugs also prolong the QT interval, adding to the risk of torsades de pointes.
How serious is the interaction between Quinidine and Risperidone?
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 used, start risperidone at a low dose, titrate cautiously, and monitor ECG, electrolytes 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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