Drug interactions
Clarithromycin + Memantine-donepezil
Severity: Major
Clarithromycin and Memantine-donepezil: major interaction.
Last updated Sources: Health Canada product monograph
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
Clarithromycin prolongs the QT interval and inhibits CYP3A4, which contributes to donepezil metabolism. This can raise donepezil exposure and add to the arrhythmic risk from both drugs.
What this interaction means in plain words
Clarithromycin and Memantine-donepezil can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Clarithromycin belongs to Anti Bacterial; Memantine-donepezil belongs to Central Nervous System.
Why it happens
Additive QT prolongation plus CYP3A4 inhibition by clarithromycin that may raise donepezil concentrations.
What to do
Prefer a non-macrolide antibiotic such as amoxicillin or doxycycline where appropriate. If clarithromycin is required, monitor the ECG and watch for bradycardia and cholinergic effects.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
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 Clarithromycin
- Astemizole + Clarithromycin Contraindicated
- Avanafil + Clarithromycin Contraindicated
- Cisapride + Clarithromycin Contraindicated
- Clarithromycin + Colchicine Contraindicated
- Clarithromycin + Conivaptan Contraindicated
- Clarithromycin + Dihydroergotamine Contraindicated
Frequently asked questions
Can I take Clarithromycin with Memantine-donepezil?
MediHelp rates the interaction as major. Clarithromycin and Memantine-donepezil can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Clarithromycin prolongs the QT interval and inhibits CYP3A4, which contributes to donepezil metabolism. This can raise donepezil exposure and add to the arrhythmic risk from both drugs.
How serious is the interaction between Clarithromycin and Memantine-donepezil?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-macrolide antibiotic such as amoxicillin or doxycycline where appropriate. If clarithromycin is required, monitor the ECG and watch for bradycardia and cholinergic effects.
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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