Drug interactions
Donepezil + Oxybutynin
Severity: Moderate
Donepezil and Oxybutynin: 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
Donepezil increases cholinergic activity while oxybutynin blocks muscarinic receptors, so each can reduce the benefit of the other. In dementia patients the anticholinergic can worsen cognition and negate the effect of the cholinesterase inhibitor.
What this interaction means in plain words
Donepezil and Oxybutynin 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.
Donepezil belongs to Central Nervous System; Oxybutynin belongs to Genitourinary.
Why it happens
Pharmacodynamic antagonism between a cholinesterase inhibitor and a muscarinic antagonist.
What to do
Avoid oxybutynin in patients taking donepezil for dementia where possible; consider mirabegron or a non-pharmacological approach. If continued, monitor cognition and urinary symptoms.
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 Oxybutynin
Other interactions of Donepezil
- Donepezil + Dronedarone Contraindicated
- Donepezil + Pimozide Contraindicated
- Donepezil + Thioridazine Contraindicated
- Donepezil + Vandetanib Contraindicated
- Amiodarone + Donepezil Major
- Amisulpride + Donepezil Major
Frequently asked questions
Can I take Donepezil with Oxybutynin?
MediHelp rates the interaction as moderate. Donepezil and Oxybutynin 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. Donepezil increases cholinergic activity while oxybutynin blocks muscarinic receptors, so each can reduce the benefit of the other. In dementia patients the anticholinergic can worsen cognition and negate the effect of the cholinesterase inhibitor.
How serious is the interaction between Donepezil and Oxybutynin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid oxybutynin in patients taking donepezil for dementia where possible; consider mirabegron or a non-pharmacological approach. If continued, monitor cognition and urinary symptoms.
What other medicines interact with Oxybutynin?
MediHelp also lists interactions of Oxybutynin with, for example, Bethanechol, Clozapine, Potassium chloride. The full list is on the Oxybutynin page.
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