Drug interactions
Foscarnet + Moxifloxacin
Severity: Major
Foscarnet and Moxifloxacin: major 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 are associated with QT prolongation, and foscarnet also commonly causes hypocalcemia, hypomagnesemia and hypokalemia that further raise the risk of torsades de pointes.
What this interaction means in plain words
Foscarnet and Moxifloxacin 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.
Foscarnet belongs to Anti Virals; Moxifloxacin belongs to Anti Bacterial.
Why it happens
Additive hERG-mediated QT prolongation, worsened by foscarnet-induced electrolyte depletion.
What to do
Avoid if an alternative antibiotic exists. If combined, monitor ECG and serum calcium, magnesium and potassium and replace deficits promptly.
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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Other interactions of Moxifloxacin
- Amiodarone + Moxifloxacin Contraindicated
- Arsenic trioxide + Moxifloxacin Contraindicated
- Disopyramide + Moxifloxacin Contraindicated
- Dofetilide + Moxifloxacin Contraindicated
- Dronedarone + Moxifloxacin Contraindicated
- Droperidol + Moxifloxacin 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 Foscarnet with Moxifloxacin?
MediHelp rates the interaction as major. Foscarnet and Moxifloxacin 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 are associated with QT prolongation, and foscarnet also commonly causes hypocalcemia, hypomagnesemia and hypokalemia that further raise the risk of torsades de pointes.
How serious is the interaction between Foscarnet and Moxifloxacin?
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 if an alternative antibiotic exists. If combined, monitor ECG and serum calcium, magnesium and potassium and replace deficits promptly.
What other medicines interact with Moxifloxacin?
MediHelp also lists interactions of Moxifloxacin with, for example, Amiodarone, Arsenic trioxide, Disopyramide. The full list is on the Moxifloxacin page.
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