Drug interactions
Lapatinib + Thioridazine
Severity: Contraindicated
Lapatinib and Thioridazine: 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
Thioridazine carries a strong QT-prolonging effect and lapatinib can also lengthen the QT interval. Combined use markedly raises the risk of torsades de pointes.
What this interaction means in plain words
Lapatinib and Thioridazine 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; Thioridazine belongs to Central Nervous System.
Why it happens
Additive prolongation of cardiac repolarization through cardiac potassium channel effects.
What to do
Avoid using the two together and select an alternative antipsychotic with lower QT liability.
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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Adagrasib + Lapatinib Major
- Amiodarone + Lapatinib Major
Frequently asked questions
Can I take Lapatinib with Thioridazine?
MediHelp rates the interaction as contraindicated. Lapatinib and Thioridazine 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. Thioridazine carries a strong QT-prolonging effect and lapatinib can also lengthen the QT interval. Combined use markedly raises the risk of torsades de pointes.
How serious is the interaction between Lapatinib and Thioridazine?
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 using the two together and select an alternative antipsychotic with lower QT liability.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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