Drug interactions
Quinupristin / dalfopristin + Tolterodine
Severity: Moderate
Quinupristin / dalfopristin 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
Quinupristin/dalfopristin inhibits CYP3A4 and can raise levels of CYP3A4 substrates. Tolterodine exposure may rise, mainly in CYP2D6 poor metabolizers, increasing anticholinergic effects and QT risk.
What this interaction means in plain words
Quinupristin / dalfopristin 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.
Why it happens
CYP3A4 inhibition by quinupristin/dalfopristin reduces tolterodine metabolism.
What to do
Monitor for anticholinergic adverse effects and consider a lower tolterodine dose. Check ECG if other QT-prolonging drugs are used.
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
Frequently asked questions
Can I take Quinupristin / dalfopristin with Tolterodine?
MediHelp rates the interaction as moderate. Quinupristin / dalfopristin 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. Quinupristin/dalfopristin inhibits CYP3A4 and can raise levels of CYP3A4 substrates. Tolterodine exposure may rise, mainly in CYP2D6 poor metabolizers, increasing anticholinergic effects and QT risk.
How serious is the interaction between Quinupristin / dalfopristin 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 adverse effects and consider a lower tolterodine dose. Check ECG if other QT-prolonging drugs are used.
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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