Drug interactions
Azithromycin + Erythromycin
Severity: Moderate
Azithromycin and Erythromycin: moderate 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
Both macrolides can prolong the QT interval, so combining them adds to the risk of torsades de pointes, particularly with other risk factors. There is also no therapeutic benefit from using two macrolides together.
What this interaction means in plain words
Azithromycin and Erythromycin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Azithromycin belongs to Anti Bacterial; Erythromycin belongs to Anti Bacterial.
Why it happens
Additive blockade of cardiac IKr potassium channels causing QT prolongation.
What to do
Avoid concurrent use of two macrolides. If unavoidable, obtain an ECG and correct potassium and magnesium.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
Other interactions of Azithromycin
- Azithromycin + Cisapride Contraindicated
- Azithromycin + Domperidone Contraindicated
- Azithromycin + Dronedarone Contraindicated
- Azithromycin + Pimozide Contraindicated
- Azithromycin + Piperaquine Contraindicated
- Azithromycin + Thioridazine Contraindicated
Frequently asked questions
Can I take Azithromycin with Erythromycin?
MediHelp rates the interaction as moderate. Azithromycin and Erythromycin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both macrolides can prolong the QT interval, so combining them adds to the risk of torsades de pointes, particularly with other risk factors. There is also no therapeutic benefit from using two macrolides together.
How serious is the interaction between Azithromycin and Erythromycin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use of two macrolides. If unavoidable, obtain an ECG and correct potassium and magnesium.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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