Drug interactions
Erythromycin base + Moxifloxacin
Severity: Major
Erythromycin base and Moxifloxacin: major interaction.
Last updated Sources: US FDA label
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 prolong the QT interval, and erythromycin is associated with torsades de pointes. Using them together increases the risk of life-threatening arrhythmia.
What this interaction means in plain words
Erythromycin base 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.
Why it happens
Additive pharmacodynamic QT prolongation via hERG potassium channel blockade.
What to do
Avoid the combination and choose an antibiotic regimen with less QT effect. If it is essential, monitor ECG and correct potassium and magnesium.
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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References
Other interactions of Moxifloxacin
- Amiodarone + Moxifloxacin Contraindicated
- Arsenic trioxide + Moxifloxacin Contraindicated
- Disopyramide + Moxifloxacin Contraindicated
- Dofetilide + Moxifloxacin Contraindicated
- Dronedarone + Moxifloxacin Contraindicated
- Droperidol + Moxifloxacin Contraindicated
Frequently asked questions
Can I take Erythromycin base with Moxifloxacin?
MediHelp rates the interaction as major. Erythromycin base 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 agents prolong the QT interval, and erythromycin is associated with torsades de pointes. Using them together increases the risk of life-threatening arrhythmia.
How serious is the interaction between Erythromycin base 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 the combination and choose an antibiotic regimen with less QT effect. If it is essential, monitor ECG and correct potassium and magnesium.
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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