Drug interactions
Erythromycin + Fluoxetine
Severity: Moderate
Erythromycin and Fluoxetine: 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
Erythromycin and fluoxetine can each prolong the QT interval, so combining them adds to the risk of arrhythmia including torsades de pointes. Fluoxetine inhibits CYP3A4 weakly and CYP2D6 strongly, which is unlikely to alter erythromycin much.
What this interaction means in plain words
Erythromycin and Fluoxetine 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.
Erythromycin belongs to Anti Bacterial; Fluoxetine belongs to Central Nervous System.
Why it happens
Additive QT-prolonging pharmacodynamic effects.
What to do
Check ECG and electrolytes if there are other risk factors for QT prolongation; consider an alternative antibiotic in high-risk patients.
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?
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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 Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Erythromycin with Fluoxetine?
MediHelp rates the interaction as moderate. Erythromycin and Fluoxetine 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. Erythromycin and fluoxetine can each prolong the QT interval, so combining them adds to the risk of arrhythmia including torsades de pointes. Fluoxetine inhibits CYP3A4 weakly and CYP2D6 strongly, which is unlikely to alter erythromycin much.
How serious is the interaction between Erythromycin and Fluoxetine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check ECG and electrolytes if there are other risk factors for QT prolongation; consider an alternative antibiotic in high-risk patients.
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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