Drug interactions
Methadone + Moxifloxacin
Severity: Major
Methadone 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 prolong the QT interval, so combining them raises the risk of torsades de pointes and other ventricular arrhythmias. The risk is greater with higher methadone doses, hypokalemia, hypomagnesemia, bradycardia or underlying heart disease.
What this interaction means in plain words
Methadone 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.
Methadone belongs to Musculoskeletal; Moxifloxacin belongs to Anti Bacterial.
Why it happens
Additive QT prolongation through blockade of cardiac hERG potassium channels.
What to do
Prefer a non-QT-prolonging antibiotic when possible. If combined, obtain a baseline and follow-up ECG and correct potassium and magnesium abnormalities.
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 Methadone
- Alvimopan + Methadone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Methadone Contraindicated
- Droperidol + Methadone Contraindicated
- Ibutilide + Methadone Contraindicated
- Isocarboxazid + Methadone Contraindicated
- Lefamulin + Methadone Contraindicated
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 Methadone with Moxifloxacin?
MediHelp rates the interaction as major. Methadone 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 prolong the QT interval, so combining them raises the risk of torsades de pointes and other ventricular arrhythmias. The risk is greater with higher methadone doses, hypokalemia, hypomagnesemia, bradycardia or underlying heart disease.
How serious is the interaction between Methadone 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: Prefer a non-QT-prolonging antibiotic when possible. If combined, obtain a baseline and follow-up ECG and correct potassium and magnesium abnormalities.
What other medicines interact with Methadone?
MediHelp also lists interactions of Methadone with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Droperidol. The full list is on the Methadone page.
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