Drug interactions
Erythromycin + Fesoterodine
Severity: Moderate
Erythromycin and Fesoterodine: 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, a moderate CYP3A4 inhibitor, increases exposure to the active metabolite of fesoterodine to a modest degree. This may increase anticholinergic effects such as dry mouth, constipation and urinary retention.
What this interaction means in plain words
Erythromycin and Fesoterodine 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; Fesoterodine belongs to Genitourinary.
Why it happens
CYP3A4 inhibition reduces clearance of fesoterodine's active metabolite 5-hydroxymethyl tolterodine.
What to do
Monitor for anticholinergic adverse effects; labeling limits fesoterodine to 4 mg daily with strong CYP3A4 inhibitors, and a dose reduction can be considered if effects occur.
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 Fesoterodine
Frequently asked questions
Can I take Erythromycin with Fesoterodine?
MediHelp rates the interaction as moderate. Erythromycin and Fesoterodine 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, a moderate CYP3A4 inhibitor, increases exposure to the active metabolite of fesoterodine to a modest degree. This may increase anticholinergic effects such as dry mouth, constipation and urinary retention.
How serious is the interaction between Erythromycin and Fesoterodine?
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 anticholinergic adverse effects; labeling limits fesoterodine to 4 mg daily with strong CYP3A4 inhibitors, and a dose reduction can be considered if effects occur.
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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