Drug interactions
Cimetidine + Erythromycin ethylsuccinate
Severity: Moderate
Cimetidine and Erythromycin ethylsuccinate: moderate 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
Cimetidine can raise erythromycin concentrations. This may increase GI effects and, rarely, QT prolongation or ototoxicity.
What this interaction means in plain words
Cimetidine and Erythromycin ethylsuccinate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Cimetidine inhibits CYP3A4, reducing erythromycin metabolism.
What to do
Monitor for adverse effects and consider an ECG if other QT-prolonging drugs or risk factors are present. Use famotidine as an alternative where appropriate.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Cimetidine and Erythromycin ethylsuccinate, 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.
Other interactions of Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Frequently asked questions
Can I take Cimetidine with Erythromycin ethylsuccinate?
MediHelp rates the interaction as moderate. Cimetidine and Erythromycin ethylsuccinate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Cimetidine can raise erythromycin concentrations. This may increase GI effects and, rarely, QT prolongation or ototoxicity.
How serious is the interaction between Cimetidine and Erythromycin ethylsuccinate?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for adverse effects and consider an ECG if other QT-prolonging drugs or risk factors are present. Use famotidine as an alternative where appropriate.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine 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.
