Drug interactions
Erythromycin ethylsuccinate + Theophylline
Severity: Major
Erythromycin ethylsuccinate and Theophylline: 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 reduces theophylline clearance and can raise serum levels, sometimes into the toxic range. Toxicity includes nausea, tachycardia, arrhythmias and seizures. The effect usually builds over several days of combined use.
What this interaction means in plain words
Erythromycin ethylsuccinate and Theophylline 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
Erythromycin inhibits hepatic CYP3A4 and to some extent CYP1A2, lowering theophylline metabolism.
What to do
Consider an alternative antibiotic such as azithromycin; if erythromycin is needed, reduce the theophylline dose and monitor serum concentrations during and after the course.
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 ethylsuccinate and Theophylline, 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
- Ery-Ped - FDA drug label (DailyMed) — openFDA / DailyMed
Other interactions of Theophylline
- Riociguat + Theophylline Contraindicated
- Adenosine + Theophylline Major
- Apalutamide + Theophylline Major
- Bupropion + Theophylline Major
- Carvedilol + Theophylline Major
- Cimetidine + Theophylline Major
Frequently asked questions
Can I take Erythromycin ethylsuccinate with Theophylline?
MediHelp rates the interaction as major. Erythromycin ethylsuccinate and Theophylline 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 reduces theophylline clearance and can raise serum levels, sometimes into the toxic range. Toxicity includes nausea, tachycardia, arrhythmias and seizures. The effect usually builds over several days of combined use.
How serious is the interaction between Erythromycin ethylsuccinate and Theophylline?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Consider an alternative antibiotic such as azithromycin; if erythromycin is needed, reduce the theophylline dose and monitor serum concentrations during and after the course.
What other medicines interact with Theophylline?
MediHelp also lists interactions of Theophylline with, for example, Riociguat, Adenosine, Apalutamide. The full list is on the Theophylline 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.
