Drug interactions
Fesoterodine + Terbinafine
Severity: Minor
Fesoterodine and Terbinafine: minor 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
Terbinafine is a strong CYP2D6 inhibitor and can raise exposure to the active metabolite of fesoterodine (5-hydroxymethyl tolterodine), which is partly cleared via CYP2D6. This may increase antimuscarinic adverse effects. The effect is usually modest because CYP3A4 provides an alternative elimination route.
What this interaction means in plain words
Fesoterodine and Terbinafine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fesoterodine belongs to Genitourinary; Terbinafine belongs to Anti Fungals.
Why it happens
Inhibition of CYP2D6-mediated metabolism of the active metabolite of fesoterodine.
What to do
Monitor for anticholinergic effects such as dry mouth and constipation during terbinafine therapy. Reduce the fesoterodine dose if adverse effects become troublesome.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Fesoterodine
Other interactions of Terbinafine
- Terbinafine + Thioridazine Contraindicated
- Desipramine + Terbinafine Major
- Eliglustat + Terbinafine Major
- Flecainide + Terbinafine Major
- Imipramine + Terbinafine Major
- Maprotiline + Terbinafine Major
Frequently asked questions
Can I take Fesoterodine with Terbinafine?
MediHelp rates the interaction as minor. Fesoterodine and Terbinafine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Terbinafine is a strong CYP2D6 inhibitor and can raise exposure to the active metabolite of fesoterodine (5-hydroxymethyl tolterodine), which is partly cleared via CYP2D6. This may increase antimuscarinic adverse effects. The effect is usually modest because CYP3A4 provides an alternative elimination route.
How serious is the interaction between Fesoterodine and Terbinafine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for anticholinergic effects such as dry mouth and constipation during terbinafine therapy. Reduce the fesoterodine dose if adverse effects become troublesome.
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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