Drug interactions
Erythromycin + Methadone
Severity: Major
Erythromycin and Methadone: 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
Erythromycin can raise methadone levels, leading to opioid toxicity including respiratory depression. Both drugs also prolong the QT interval, adding to the risk of torsades de pointes.
What this interaction means in plain words
Erythromycin and Methadone 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.
Erythromycin belongs to Anti Bacterial; Methadone belongs to Musculoskeletal.
Why it happens
Erythromycin inhibits CYP3A4 (and partly CYP2B6-mediated pathways), reducing methadone clearance, with additive QT effects.
What to do
Prefer an alternative antibiotic. If combined, monitor sedation, respiratory rate and QTc, and reduce the methadone dose as needed.
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 Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
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
Frequently asked questions
Can I take Erythromycin with Methadone?
MediHelp rates the interaction as major. Erythromycin and Methadone 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. Erythromycin can raise methadone levels, leading to opioid toxicity including respiratory depression. Both drugs also prolong the QT interval, adding to the risk of torsades de pointes.
How serious is the interaction between Erythromycin and Methadone?
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 an alternative antibiotic. If combined, monitor sedation, respiratory rate and QTc, and reduce the methadone dose as needed.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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