Drug interactions
Erythromycin lactobionate + Memantine-donepezil
Severity: Major
Erythromycin lactobionate 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
Donepezil can prolong the QT interval and has been linked to torsades de pointes. Intravenous erythromycin lactobionate also prolongs QT, and the risk is higher with IV dosing, so the combination increases the likelihood of serious ventricular arrhythmia. Erythromycin may also raise donepezil exposure via CYP3A4 inhibition.
What this interaction means in plain words
Erythromycin lactobionate 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 lactobionate belongs to Anti Bacterial; Memantine-donepezil belongs to Central Nervous System.
Why it happens
Additive QT prolongation through cardiac potassium channel effects, with possible CYP3A4 inhibition by erythromycin increasing donepezil levels.
What to do
Choose an alternative antibiotic without QT effects where feasible. If unavoidable, check a baseline ECG, correct electrolytes, and monitor the QTc and heart rhythm during infusion.
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
Other interactions of Erythromycin lactobionate
- Cisapride + Erythromycin lactobionate Contraindicated
- Dihydroergotamine + Erythromycin lactobionate Contraindicated
- Dronedarone + Erythromycin lactobionate Contraindicated
- Eletriptan + Erythromycin lactobionate Contraindicated
- Ergotamine + Erythromycin lactobionate Contraindicated
- Erythromycin lactobionate + Flibanserin Contraindicated
Frequently asked questions
Can I take Erythromycin lactobionate with Memantine-donepezil?
MediHelp rates the interaction as major. Erythromycin lactobionate 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. Donepezil can prolong the QT interval and has been linked to torsades de pointes. Intravenous erythromycin lactobionate also prolongs QT, and the risk is higher with IV dosing, so the combination increases the likelihood of serious ventricular arrhythmia. Erythromycin may also raise donepezil exposure via CYP3A4 inhibition.
How serious is the interaction between Erythromycin lactobionate 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: Choose an alternative antibiotic without QT effects where feasible. If unavoidable, check a baseline ECG, correct electrolytes, and monitor the QTc and heart rhythm during infusion.
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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