Drug interactions
Fluphenazine + Tolterodine
Severity: Moderate
Fluphenazine 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
Fluphenazine has anticholinergic properties, so with tolterodine the antimuscarinic effects add up and can cause dry mouth, constipation, urinary retention, blurred vision and confusion. Both drugs can prolong the QT interval, and fluphenazine inhibits CYP2D6, which may raise tolterodine exposure.
What this interaction means in plain words
Fluphenazine 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.
Fluphenazine belongs to Central Nervous System; Tolterodine belongs to Genitourinary.
Why it happens
Additive antimuscarinic and QT-prolonging effects, with possible CYP2D6 inhibition by fluphenazine.
What to do
Monitor for anticholinergic toxicity and consider an ECG if other QT risk factors exist. Use the lowest effective tolterodine dose, especially in older patients.
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 Fluphenazine
- Arsenic trioxide + Fluphenazine Contraindicated
- Dofetilide + Fluphenazine Contraindicated
- Fluphenazine + Ibutilide Contraindicated
- Fluphenazine + Pimozide Contraindicated
- Adagrasib + Fluphenazine Major
- Alfentanil + Fluphenazine Major
Frequently asked questions
Can I take Fluphenazine with Tolterodine?
MediHelp rates the interaction as moderate. Fluphenazine 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. Fluphenazine has anticholinergic properties, so with tolterodine the antimuscarinic effects add up and can cause dry mouth, constipation, urinary retention, blurred vision and confusion. Both drugs can prolong the QT interval, and fluphenazine inhibits CYP2D6, which may raise tolterodine exposure.
How serious is the interaction between Fluphenazine 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 toxicity and consider an ECG if other QT risk factors exist. Use the lowest effective tolterodine dose, especially in older patients.
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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