Drug interactions
Tolterodine + Tucatinib
Severity: Moderate
Tolterodine and Tucatinib: 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
Tucatinib is a strong CYP3A inhibitor and may increase tolterodine concentrations, particularly in CYP2D6 poor metabolizers. This can lead to greater anticholinergic toxicity and QT prolongation.
What this interaction means in plain words
Tolterodine and Tucatinib 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.
Tolterodine belongs to Genitourinary; Tucatinib belongs to Oncology.
Why it happens
Tucatinib inhibits CYP3A4, reducing tolterodine's alternative metabolic clearance.
What to do
Reduce tolterodine to 1 mg twice daily or use an alternative antimuscarinic, and monitor for urinary retention, dry mouth, 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 Tolterodine
Other interactions of Tucatinib
- Cisapride + Tucatinib Contraindicated
- Eletriptan + Tucatinib Contraindicated
- Ergotamine + Tucatinib Contraindicated
- Flibanserin + Tucatinib Contraindicated
- Ranolazine + Tucatinib Contraindicated
- Amobarbital + Tucatinib Major
Frequently asked questions
Can I take Tolterodine with Tucatinib?
MediHelp rates the interaction as moderate. Tolterodine and Tucatinib 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. Tucatinib is a strong CYP3A inhibitor and may increase tolterodine concentrations, particularly in CYP2D6 poor metabolizers. This can lead to greater anticholinergic toxicity and QT prolongation.
How serious is the interaction between Tolterodine and Tucatinib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce tolterodine to 1 mg twice daily or use an alternative antimuscarinic, and monitor for urinary retention, dry mouth, and palpitations.
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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