Drug interactions
Erythromycin base + Memantine-donepezil
Severity: Major
Erythromycin base and Memantine-donepezil: major 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
Erythromycin can prolong the QT interval and cause torsades de pointes, and donepezil adds to this risk. Erythromycin may also modestly raise donepezil exposure by inhibiting CYP3A4.
What this interaction means in plain words
Erythromycin base 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.
Why it happens
Additive QT prolongation, plus CYP3A4 inhibition by erythromycin that may increase donepezil levels.
What to do
Prefer a non-macrolide antibiotic with less QT liability, such as one without QT effects. If erythromycin is needed, check ECG and electrolytes and monitor for 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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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 Erythromycin base with Memantine-donepezil?
MediHelp rates the interaction as major. Erythromycin base 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. Erythromycin can prolong the QT interval and cause torsades de pointes, and donepezil adds to this risk. Erythromycin may also modestly raise donepezil exposure by inhibiting CYP3A4.
How serious is the interaction between Erythromycin base 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 with less QT liability, such as one without QT effects. If erythromycin is needed, check ECG and electrolytes and monitor for 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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