Drug interactions
Doxepin + Memantine-donepezil
Severity: Moderate
Doxepin and Memantine-donepezil: 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 with strong anticholinergic activity that can counteract donepezil and worsen cognition. Both drugs may also prolong the QT interval, and doxepin adds sedation and orthostatic hypotension risks.
What this interaction means in plain words
Doxepin and Memantine-donepezil 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 belongs to Dermatology; Memantine-donepezil belongs to Central Nervous System.
Why it happens
Antimuscarinic antagonism of cholinesterase inhibition plus additive QT prolongation.
What to do
Prefer a non-anticholinergic alternative in dementia, or use low-dose doxepin with monitoring of cognition, heart rate and ECG. Correct electrolyte disturbances.
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 Memantine-donepezil
- Dronedarone + Memantine-donepezil Contraindicated
- Memantine-donepezil + Thioridazine Contraindicated
- Amantadine + Memantine-donepezil Major
- Amiodarone + Memantine-donepezil Major
- Amisulpride + Memantine-donepezil Major
- Amitriptyline + Memantine-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 Doxepin with Memantine-donepezil?
MediHelp rates the interaction as moderate. Doxepin and Memantine-donepezil 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 with strong anticholinergic activity that can counteract donepezil and worsen cognition. Both drugs may also prolong the QT interval, and doxepin adds sedation and orthostatic hypotension risks.
How serious is the interaction between Doxepin and Memantine-donepezil?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-anticholinergic alternative in dementia, or use low-dose doxepin with monitoring of cognition, heart rate and ECG. Correct electrolyte disturbances.
What other medicines interact with Memantine-donepezil?
MediHelp also lists interactions of Memantine-donepezil with, for example, Dronedarone, Thioridazine, Amantadine. The full list is on the Memantine-donepezil page.
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