Drug interactions
Azithromycin + Promethazine
Severity: Moderate
Azithromycin and Promethazine: 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 drugs have been associated with QT prolongation, so combining them may increase the risk of torsades de pointes. The risk is greater with electrolyte disturbance, heart disease or other QT-prolonging drugs.
What this interaction means in plain words
Azithromycin and Promethazine 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; Promethazine belongs to Respiratory.
Why it happens
Additive blockade of cardiac potassium channels prolonging repolarization.
What to do
Correct hypokalemia and hypomagnesemia and obtain an ECG in patients with cardiac risk factors. Choose a non-QT-prolonging alternative if risk is high.
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 Promethazine
- Cabergoline + Promethazine Contraindicated
- Dopamine + Promethazine Contraindicated
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
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 Promethazine?
MediHelp rates the interaction as moderate. Azithromycin and Promethazine 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 drugs have been associated with QT prolongation, so combining them may increase the risk of torsades de pointes. The risk is greater with electrolyte disturbance, heart disease or other QT-prolonging drugs.
How serious is the interaction between Azithromycin and Promethazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Correct hypokalemia and hypomagnesemia and obtain an ECG in patients with cardiac risk factors. Choose a non-QT-prolonging alternative if risk is high.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Cabergoline, Dopamine, Ibutilide. The full list is on the Promethazine page.
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