Drug interactions
Lapatinib + Selpercatinib
Severity: Major
Lapatinib and Selpercatinib: 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
Both agents can prolong the QT interval, so combination raises the risk of torsades de pointes, especially with electrolyte disturbances or cardiac disease.
What this interaction means in plain words
Lapatinib and Selpercatinib 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; Selpercatinib belongs to Oncology.
Why it happens
Additive QT interval prolongation.
What to do
Obtain baseline and follow-up ECGs, correct potassium and magnesium, and interrupt or reduce therapy if QTc becomes markedly prolonged.
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 Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Other interactions of Selpercatinib
Frequently asked questions
Can I take Lapatinib with Selpercatinib?
MediHelp rates the interaction as major. Lapatinib and Selpercatinib 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. Both agents can prolong the QT interval, so combination raises the risk of torsades de pointes, especially with electrolyte disturbances or cardiac disease.
How serious is the interaction between Lapatinib and Selpercatinib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain baseline and follow-up ECGs, correct potassium and magnesium, and interrupt or reduce therapy if QTc becomes markedly prolonged.
What other medicines interact with Lapatinib?
MediHelp also lists interactions of Lapatinib with, for example, Dofetilide, Ibutilide, Pimozide. The full list is on the Lapatinib page.
Full monographs, dosing and an interaction checker in the MediHelp app
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