Drug interactions
Azithromycin + Quinidine
Severity: Major
Azithromycin and Quinidine: major interaction.
Last updated Sources: UK SmPC
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 drugs prolong the QT interval, and the combination raises the risk of torsades de pointes and sudden cardiac death. Quinidine already carries a notable proarrhythmic risk.
What this interaction means in plain words
Azithromycin 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.
Azithromycin belongs to Anti Bacterial; Quinidine belongs to Anti Parasitic.
Why it happens
Additive QT prolongation through potassium channel blockade.
What to do
Avoid the combination where possible and choose a non-QT-prolonging antibiotic; if used, monitor ECG and keep potassium and magnesium normal.
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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References
- Azithromycin 200mg/5ml Powder for Oral Suspension - SmPC sections 4.3/4.5 (names the partner; "with caution in patients receiving medicinal products known to prolong the QT interval (see section 4.4), such as antiarrhythmics of Classes IA (e.g. quinidine ") — electronic medicines compendium (UK SmPC)
Other interactions of Azithromycin
- Azithromycin + Cisapride Contraindicated
- Azithromycin + Domperidone Contraindicated
- Azithromycin + Dronedarone Contraindicated
- Azithromycin + Pimozide Contraindicated
- Azithromycin + Piperaquine Contraindicated
- Azithromycin + Thioridazine Contraindicated
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 Azithromycin with Quinidine?
MediHelp rates the interaction as major. Azithromycin 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. Both drugs prolong the QT interval, and the combination raises the risk of torsades de pointes and sudden cardiac death. Quinidine already carries a notable proarrhythmic risk.
How serious is the interaction between Azithromycin 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 where possible and choose a non-QT-prolonging antibiotic; if used, monitor ECG and keep potassium and magnesium normal.
What other medicines interact with Azithromycin?
MediHelp also lists interactions of Azithromycin with, for example, Cisapride, Domperidone, Dronedarone. The full list is on the Azithromycin page.
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