Drug interactions
Lapatinib + Pimozide
Severity: Contraindicated
Lapatinib and Pimozide: contraindicated 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 prolongs the QT interval and inhibits CYP3A4, which contributes to pimozide metabolism. Higher pimozide levels plus additive QT effects raise the risk of torsades de pointes.
What this interaction means in plain words
Lapatinib and Pimozide are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Lapatinib belongs to Oncology; Pimozide belongs to Central Nervous System.
Why it happens
Additive QT prolongation plus CYP3A4 inhibition by lapatinib reducing pimozide clearance.
What to do
Avoid the combination. Choose an alternative for Tourette's or psychosis that is not a narrow-index CYP3A substrate.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide Contraindicated
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
- Amiodarone + Lapatinib Major
Frequently asked questions
Can I take Lapatinib with Pimozide?
MediHelp rates the interaction as contraindicated. Lapatinib and Pimozide are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Lapatinib prolongs the QT interval and inhibits CYP3A4, which contributes to pimozide metabolism. Higher pimozide levels plus additive QT effects raise the risk of torsades de pointes.
How serious is the interaction between Lapatinib and Pimozide?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination. Choose an alternative for Tourette's or psychosis that is not a narrow-index CYP3A substrate.
What other medicines interact with Pimozide?
MediHelp also lists interactions of Pimozide with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Pimozide page.
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