Drug interactions
Lapatinib + Olanzapine
Severity: Moderate
Lapatinib and Olanzapine: 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
Both drugs can prolong the QT interval, so combined use may increase the risk of torsades de pointes. The risk is greater with electrolyte disturbances or other QT-prolonging factors.
What this interaction means in plain words
Lapatinib and Olanzapine 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; Olanzapine belongs to Central Nervous System.
Why it happens
Additive prolongation of cardiac repolarization through effects on cardiac potassium channels.
What to do
Obtain a baseline ECG and monitor QTc periodically, and correct potassium and magnesium abnormalities. Consider an alternative if QTc becomes markedly prolonged.
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 Olanzapine
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 Olanzapine?
MediHelp rates the interaction as moderate. Lapatinib and Olanzapine 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. Both drugs can prolong the QT interval, so combined use may increase the risk of torsades de pointes. The risk is greater with electrolyte disturbances or other QT-prolonging factors.
How serious is the interaction between Lapatinib and Olanzapine?
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 monitor QTc periodically, and correct potassium and magnesium abnormalities. Consider an alternative if QTc becomes markedly prolonged.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
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