Drug interactions
Terbinafine + Tolterodine
Severity: Moderate
Terbinafine 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
Terbinafine is a potent CYP2D6 inhibitor and can raise tolterodine levels. Tolterodine is also cleared via CYP3A4, which partly compensates, but anticholinergic effects and QT effects may still increase.
What this interaction means in plain words
Terbinafine 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.
Terbinafine belongs to Anti Fungals; Tolterodine belongs to Genitourinary.
Why it happens
Terbinafine inhibits CYP2D6, reducing conversion of tolterodine to its active 5-hydroxymethyl metabolite and increasing parent drug exposure.
What to do
Monitor for anticholinergic effects and consider limiting tolterodine to 1 mg twice daily or less if adverse 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 Tolterodine
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 Terbinafine with Tolterodine?
MediHelp rates the interaction as moderate. Terbinafine 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. Terbinafine is a potent CYP2D6 inhibitor and can raise tolterodine levels. Tolterodine is also cleared via CYP3A4, which partly compensates, but anticholinergic effects and QT effects may still increase.
How serious is the interaction between Terbinafine 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: Monitor for anticholinergic effects and consider limiting tolterodine to 1 mg twice daily or less if adverse effects occur.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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