Drug interactions
Erythromycin + Tolterodine
Severity: Moderate
Erythromycin and Tolterodine: 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 can raise tolterodine concentrations, mainly in patients who lack CYP2D6 activity and rely on CYP3A4 for clearance. Higher exposure increases anticholinergic effects and may contribute to QT prolongation.
What this interaction means in plain words
Erythromycin and Tolterodine 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; Tolterodine belongs to Genitourinary.
Why it happens
Erythromycin inhibits CYP3A4-mediated metabolism of tolterodine.
What to do
Limit tolterodine to 1 mg twice daily during coadministration with strong or moderate CYP3A4 inhibitors per labeling, and monitor for anticholinergic effects and palpitations.
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 Tolterodine
Frequently asked questions
Can I take Erythromycin with Tolterodine?
MediHelp rates the interaction as moderate. Erythromycin and Tolterodine 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 can raise tolterodine concentrations, mainly in patients who lack CYP2D6 activity and rely on CYP3A4 for clearance. Higher exposure increases anticholinergic effects and may contribute to QT prolongation.
How serious is the interaction between Erythromycin and Tolterodine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit tolterodine to 1 mg twice daily during coadministration with strong or moderate CYP3A4 inhibitors per labeling, and monitor for anticholinergic effects and palpitations.
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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