Drug interactions
Lapatinib + Quetiapine
Severity: Major
Lapatinib and Quetiapine: 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
Lapatinib inhibits CYP3A4 and can raise quetiapine exposure, increasing sedation and hypotension. Both drugs can also prolong the QT interval, so the combination adds to arrhythmia risk.
What this interaction means in plain words
Lapatinib and Quetiapine 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.
Lapatinib belongs to Oncology; Quetiapine belongs to Central Nervous System.
Why it happens
CYP3A4 inhibition by lapatinib reduces quetiapine clearance, with additive QT prolongation.
What to do
Consider reducing the quetiapine dose while on lapatinib and monitor for sedation and hypotension. Obtain a baseline and follow-up ECG and keep potassium and magnesium in the normal range.
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 Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine 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 Quetiapine?
MediHelp rates the interaction as major. Lapatinib and Quetiapine 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. Lapatinib inhibits CYP3A4 and can raise quetiapine exposure, increasing sedation and hypotension. Both drugs can also prolong the QT interval, so the combination adds to arrhythmia risk.
How serious is the interaction between Lapatinib and Quetiapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Consider reducing the quetiapine dose while on lapatinib and monitor for sedation and hypotension. Obtain a baseline and follow-up ECG and keep potassium and magnesium in the normal range.
What other medicines interact with Quetiapine?
MediHelp also lists interactions of Quetiapine with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Quetiapine page.
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