Drug interactions
Perphenazine + Tolterodine
Severity: Moderate
Perphenazine 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
Perphenazine is a CYP2D6 substrate and inhibitor, which may raise tolterodine levels, and it also has anticholinergic activity. Together this raises the risk of anticholinergic effects and QT prolongation.
What this interaction means in plain words
Perphenazine 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.
Perphenazine belongs to Central Nervous System; Tolterodine belongs to Genitourinary.
Why it happens
CYP2D6 inhibition by perphenazine reduces tolterodine clearance, with additive antimuscarinic and QT effects.
What to do
Monitor for anticholinergic effects and consider a tolterodine dose reduction. Check the 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
Other interactions of Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Frequently asked questions
Can I take Perphenazine with Tolterodine?
MediHelp rates the interaction as moderate. Perphenazine 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. Perphenazine is a CYP2D6 substrate and inhibitor, which may raise tolterodine levels, and it also has anticholinergic activity. Together this raises the risk of anticholinergic effects and QT prolongation.
How serious is the interaction between Perphenazine 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 a tolterodine dose reduction. Check the 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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