Drug interactions
Diphenhydramine + Galantamine
Severity: Moderate
Diphenhydramine and Galantamine: 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
Diphenhydramine is strongly anticholinergic and counteracts the effect of galantamine. It may reduce cognitive benefit and increase confusion, sedation and fall risk in older patients.
What this interaction means in plain words
Diphenhydramine and Galantamine 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.
Diphenhydramine belongs to Respiratory; Galantamine belongs to Central Nervous System.
Why it happens
Pharmacodynamic antagonism between a cholinesterase inhibitor and a muscarinic antagonist.
What to do
Avoid diphenhydramine in patients with dementia and use a non-sedating, non-anticholinergic antihistamine instead. Monitor cognition if it cannot be avoided.
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 Galantamine
- Galantamine + Memantine-donepezil Major
- Galantamine + Physostigmine Major
- Galantamine + Ponesimod Major
- Galantamine + Rivastigmine Major
- Amifampridine + Galantamine Moderate
- Amiodarone + Galantamine Moderate
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Galantamine?
MediHelp rates the interaction as moderate. Diphenhydramine and Galantamine 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. Diphenhydramine is strongly anticholinergic and counteracts the effect of galantamine. It may reduce cognitive benefit and increase confusion, sedation and fall risk in older patients.
How serious is the interaction between Diphenhydramine and Galantamine?
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 diphenhydramine in patients with dementia and use a non-sedating, non-anticholinergic antihistamine instead. Monitor cognition if it cannot be avoided.
What other medicines interact with Galantamine?
MediHelp also lists interactions of Galantamine with, for example, Memantine-donepezil, Physostigmine, Ponesimod. The full list is on the Galantamine page.
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