Drug interactions
Memantine-donepezil + St john's wort
Severity: Moderate
Memantine-donepezil and St john's wort: 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
St John's wort induces drug-metabolizing enzymes and may lower donepezil concentrations, potentially reducing its effect on cognition.
What this interaction means in plain words
Memantine-donepezil and St john's wort 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.
Why it happens
Induction of CYP3A4 increases donepezil metabolism.
What to do
Advise against St John's wort; if it is used or stopped, monitor cognitive response and adjust the donepezil dose as needed.
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
Frequently asked questions
Can I take Memantine-donepezil with St john's wort?
MediHelp rates the interaction as moderate. Memantine-donepezil and St john's wort 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. St John's wort induces drug-metabolizing enzymes and may lower donepezil concentrations, potentially reducing its effect on cognition.
How serious is the interaction between Memantine-donepezil and St john's wort?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise against St John's wort; if it is used or stopped, monitor cognitive response and adjust the donepezil dose as needed.
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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