Drug interactions
Azithromycin + Foscarnet
Severity: Moderate
Azithromycin and Foscarnet: 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 agents have been associated with QT prolongation, and their combination may increase the risk of ventricular arrhythmia. Foscarnet also causes electrolyte disturbances such as hypocalcemia, hypokalemia and hypomagnesemia, which further raise arrhythmic risk.
What this interaction means in plain words
Azithromycin and Foscarnet 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; Foscarnet belongs to Anti Virals.
Why it happens
Additive QTc prolongation, compounded by foscarnet-induced electrolyte depletion.
What to do
Monitor ECG and serum calcium, potassium and magnesium during co-administration and replace deficits promptly. Choose an alternative antibiotic if the QTc becomes markedly prolonged.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Azithromycin and Foscarnet, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
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 Foscarnet
- Cidofovir + Foscarnet Contraindicated
- Foscarnet + Pimozide Contraindicated
- Foscarnet + Thioridazine Contraindicated
- Foscarnet + Vandetanib Contraindicated
- Adagrasib + Foscarnet Major
- Adefovir + Foscarnet Major
Frequently asked questions
Can I take Azithromycin with Foscarnet?
MediHelp rates the interaction as moderate. Azithromycin and Foscarnet 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 agents have been associated with QT prolongation, and their combination may increase the risk of ventricular arrhythmia. Foscarnet also causes electrolyte disturbances such as hypocalcemia, hypokalemia and hypomagnesemia, which further raise arrhythmic risk.
How serious is the interaction between Azithromycin and Foscarnet?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor ECG and serum calcium, potassium and magnesium during co-administration and replace deficits promptly. Choose an alternative antibiotic if the QTc becomes markedly prolonged.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
