Drug interactions
Erythromycin lactobionate + Fesoterodine
Severity: Moderate
Erythromycin lactobionate 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
Intravenous erythromycin inhibits CYP3A4 and can raise exposure to the active metabolite of fesoterodine, 5-hydroxymethyl tolterodine. This may intensify anticholinergic effects such as dry mouth, constipation, urinary retention and QT effects.
What this interaction means in plain words
Erythromycin lactobionate 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 lactobionate belongs to Anti Bacterial; Fesoterodine belongs to Genitourinary.
Why it happens
CYP3A4 inhibition reduces the clearance of fesoterodine's active metabolite.
What to do
Monitor for anticholinergic adverse effects during the course of IV erythromycin and consider temporarily holding fesoterodine if symptoms 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 Fesoterodine
Other interactions of Erythromycin lactobionate
- Cisapride + Erythromycin lactobionate Contraindicated
- Dihydroergotamine + Erythromycin lactobionate Contraindicated
- Dronedarone + Erythromycin lactobionate Contraindicated
- Eletriptan + Erythromycin lactobionate Contraindicated
- Ergotamine + Erythromycin lactobionate Contraindicated
- Erythromycin lactobionate + Flibanserin Contraindicated
Frequently asked questions
Can I take Erythromycin lactobionate with Fesoterodine?
MediHelp rates the interaction as moderate. Erythromycin lactobionate 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. Intravenous erythromycin inhibits CYP3A4 and can raise exposure to the active metabolite of fesoterodine, 5-hydroxymethyl tolterodine. This may intensify anticholinergic effects such as dry mouth, constipation, urinary retention and QT effects.
How serious is the interaction between Erythromycin lactobionate 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 during the course of IV erythromycin and consider temporarily holding fesoterodine if symptoms occur.
What other medicines interact with Fesoterodine?
MediHelp also lists interactions of Fesoterodine with, for example, Bethanechol, Clozapine, Levoketoconazole. The full list is on the Fesoterodine page.
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