Drug interactions
Lapatinib + Memantine-donepezil
Severity: Moderate
Lapatinib and Memantine-donepezil: 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
Lapatinib can prolong the QT interval and donepezil has QT-prolonging potential, so combined use may increase arrhythmia risk. Lapatinib also inhibits CYP3A4 and may modestly raise donepezil levels.
What this interaction means in plain words
Lapatinib and Memantine-donepezil 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.
Lapatinib belongs to Oncology; Memantine-donepezil belongs to Central Nervous System.
Why it happens
Additive QT prolongation, with possible CYP3A4 inhibition by lapatinib.
What to do
Obtain a baseline ECG and correct electrolytes before starting. Monitor the QTc during treatment.
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
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Frequently asked questions
Can I take Lapatinib with Memantine-donepezil?
MediHelp rates the interaction as moderate. Lapatinib and Memantine-donepezil 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. Lapatinib can prolong the QT interval and donepezil has QT-prolonging potential, so combined use may increase arrhythmia risk. Lapatinib also inhibits CYP3A4 and may modestly raise donepezil levels.
How serious is the interaction between Lapatinib and Memantine-donepezil?
MediHelp rates it moderate, 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 correct electrolytes before starting. Monitor the QTc during treatment.
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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