Drug interactions
Lapatinib + Mefloquine
Severity: Moderate
Lapatinib and Mefloquine: 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 is a CYP3A4 inhibitor and can raise mefloquine exposure, which may increase mefloquine toxicity. Both drugs can also prolong the QT interval, adding arrhythmia risk.
What this interaction means in plain words
Lapatinib and Mefloquine 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; Mefloquine belongs to Anti Parasitic.
Why it happens
CYP3A4 inhibition by lapatinib reduces mefloquine metabolism, with additive QT prolongation.
What to do
Monitor the ECG and electrolytes, and watch for mefloquine neuropsychiatric effects. Consider another antimalarial.
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 Mefloquine
- Arsenic trioxide + Mefloquine Contraindicated
- Dronedarone + Mefloquine Contraindicated
- Ibutilide + Mefloquine Contraindicated
- Levoketoconazole + Mefloquine Contraindicated
- Mefloquine + Nilotinib Contraindicated
- Mefloquine + Pimozide Contraindicated
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 Mefloquine?
MediHelp rates the interaction as moderate. Lapatinib and Mefloquine 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 is a CYP3A4 inhibitor and can raise mefloquine exposure, which may increase mefloquine toxicity. Both drugs can also prolong the QT interval, adding arrhythmia risk.
How serious is the interaction between Lapatinib and Mefloquine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor the ECG and electrolytes, and watch for mefloquine neuropsychiatric effects. Consider another antimalarial.
What other medicines interact with Mefloquine?
MediHelp also lists interactions of Mefloquine with, for example, Arsenic trioxide, Dronedarone, Ibutilide. The full list is on the Mefloquine page.
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