Drug interactions
Azithromycin + Fostemsavir
Severity: Moderate
Azithromycin and Fostemsavir: 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
Fostemsavir at supratherapeutic doses has caused QT prolongation, and azithromycin also prolongs QT. Combined use may add to arrhythmia risk in patients with other predisposing factors.
What this interaction means in plain words
Azithromycin and Fostemsavir 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; Fostemsavir belongs to Anti Virals.
Why it happens
Additive QT prolongation.
What to do
Use with an ECG and electrolyte check in patients with cardiac risk factors or other QT-prolonging drugs. Consider an alternative antibiotic 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 Azithromycin
- Azithromycin + Cisapride Contraindicated
- Azithromycin + Domperidone Contraindicated
- Azithromycin + Dronedarone Contraindicated
- Azithromycin + Pimozide Contraindicated
- Azithromycin + Piperaquine Contraindicated
- Azithromycin + Thioridazine Contraindicated
Other interactions of Fostemsavir
- Apalutamide + Fostemsavir Contraindicated
- Carbamazepine + Fostemsavir Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Fostemsavir + Mitotane Contraindicated
- Fostemsavir + Phenytoin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
Frequently asked questions
Can I take Azithromycin with Fostemsavir?
MediHelp rates the interaction as moderate. Azithromycin and Fostemsavir 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. Fostemsavir at supratherapeutic doses has caused QT prolongation, and azithromycin also prolongs QT. Combined use may add to arrhythmia risk in patients with other predisposing factors.
How serious is the interaction between Azithromycin and Fostemsavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use with an ECG and electrolyte check in patients with cardiac risk factors or other QT-prolonging drugs. Consider an alternative antibiotic if risk is high.
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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