Drug interactions
Donepezil + Doxepin
Severity: Moderate
Donepezil and Doxepin: 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
Doxepin is a tricyclic antidepressant with anticholinergic activity that opposes donepezil, and both drugs may prolong the QT interval. Combined use may reduce cognitive benefit, worsen confusion and increase arrhythmia risk. Doxepin is also sedating.
What this interaction means in plain words
Donepezil and Doxepin 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; Doxepin belongs to Dermatology.
Why it happens
Anticholinergic antagonism of cholinesterase inhibition, plus additive QT prolongation.
What to do
Avoid antidepressant-dose doxepin in dementia where possible and prefer a less anticholinergic option. If used, monitor cognition, heart rate and ECG.
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 Donepezil
- Donepezil + Dronedarone Contraindicated
- Donepezil + Pimozide Contraindicated
- Donepezil + Thioridazine Contraindicated
- Donepezil + Vandetanib Contraindicated
- Amiodarone + Donepezil Major
- Amisulpride + Donepezil Major
Other interactions of Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Donepezil with Doxepin?
MediHelp rates the interaction as moderate. Donepezil and Doxepin 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. Doxepin is a tricyclic antidepressant with anticholinergic activity that opposes donepezil, and both drugs may prolong the QT interval. Combined use may reduce cognitive benefit, worsen confusion and increase arrhythmia risk. Doxepin is also sedating.
How serious is the interaction between Donepezil and Doxepin?
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 antidepressant-dose doxepin in dementia where possible and prefer a less anticholinergic option. If used, monitor cognition, heart rate and ECG.
What other medicines interact with Donepezil?
MediHelp also lists interactions of Donepezil with, for example, Dronedarone, Pimozide, Thioridazine. The full list is on the Donepezil page.
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