Drug interactions
Erythromycin + Propafenone
Severity: Major
Erythromycin and Propafenone: 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 propafenone concentrations, especially in patients lacking CYP2D6 activity or taking a CYP2D6 inhibitor. This increases the risk of proarrhythmia, conduction abnormalities, and CNS effects.
What this interaction means in plain words
Erythromycin and Propafenone 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; Propafenone belongs to Cardiovascular.
Why it happens
Erythromycin inhibits CYP3A4 (and CYP1A2 pathways of propafenone metabolism), raising propafenone levels, with additive QT effects.
What to do
Avoid if possible, or monitor ECG for QRS and QT prolongation and reduce the propafenone dose. Consider azithromycin as an alternative.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Erythromycin and Propafenone, 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.
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 Propafenone
- Dofetilide + Propafenone Contraindicated
- Dronedarone + Propafenone Contraindicated
- Nilotinib + Propafenone Contraindicated
- Nirmatrelvir / ritonavir + Propafenone Contraindicated
- Nirmatrelvir + Propafenone Contraindicated
- Pimozide + Propafenone Contraindicated
Frequently asked questions
Can I take Erythromycin with Propafenone?
MediHelp rates the interaction as major. Erythromycin and Propafenone 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 propafenone concentrations, especially in patients lacking CYP2D6 activity or taking a CYP2D6 inhibitor. This increases the risk of proarrhythmia, conduction abnormalities, and CNS effects.
How serious is the interaction between Erythromycin and Propafenone?
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 possible, or monitor ECG for QRS and QT prolongation and reduce the propafenone dose. Consider azithromycin as an alternative.
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.
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.
