Drug interactions
Memantine-donepezil + Methadone
Severity: Major
Memantine-donepezil and Methadone: 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
Methadone causes dose-related QT prolongation and torsades de pointes. Donepezil also carries QT and bradycardia risk, so combined use can heighten the risk of life-threatening arrhythmia.
What this interaction means in plain words
Memantine-donepezil and Methadone 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.
Memantine-donepezil belongs to Central Nervous System; Methadone belongs to Musculoskeletal.
Why it happens
Additive pharmacodynamic QT prolongation with donepezil-induced bradycardia.
What to do
Obtain a baseline ECG and repeat it after dose changes, and correct potassium and magnesium. Consider an alternative to either drug if the QTc is prolonged.
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 Methadone
- Alvimopan + Methadone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Methadone Contraindicated
- Droperidol + Methadone Contraindicated
- Ibutilide + Methadone Contraindicated
- Isocarboxazid + Methadone Contraindicated
- Lefamulin + Methadone Contraindicated
Frequently asked questions
Can I take Memantine-donepezil with Methadone?
MediHelp rates the interaction as major. Memantine-donepezil and Methadone 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. Methadone causes dose-related QT prolongation and torsades de pointes. Donepezil also carries QT and bradycardia risk, so combined use can heighten the risk of life-threatening arrhythmia.
How serious is the interaction between Memantine-donepezil and Methadone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and repeat it after dose changes, and correct potassium and magnesium. Consider an alternative to either drug if the QTc is prolonged.
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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