Drug interactions
Nefazodone + Quinidine
Severity: Major
Nefazodone 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
Nefazodone is a strong CYP3A4 inhibitor and can raise quinidine concentrations, which increases the risk of QT prolongation and torsades de pointes. Quinidine has a narrow therapeutic index.
What this interaction means in plain words
Nefazodone 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.
Why it happens
Nefazodone inhibits CYP3A4, reducing quinidine metabolism.
What to do
Avoid the combination and use another antidepressant. If unavoidable, reduce the quinidine dose and monitor ECG and quinidine levels.
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
Frequently asked questions
Can I take Nefazodone with Quinidine?
MediHelp rates the interaction as major. Nefazodone 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. Nefazodone is a strong CYP3A4 inhibitor and can raise quinidine concentrations, which increases the risk of QT prolongation and torsades de pointes. Quinidine has a narrow therapeutic index.
How serious is the interaction between Nefazodone 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 and use another antidepressant. If unavoidable, reduce the quinidine dose and monitor ECG and quinidine levels.
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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