Drug interactions
Lapatinib + Vemurafenib
Severity: Major
Lapatinib and Vemurafenib: 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 drugs prolong the QT interval, and vemurafenib is a CYP3A4 inducer that may lower lapatinib exposure. Arrhythmia risk is increased, and lapatinib efficacy may be reduced.
What this interaction means in plain words
Lapatinib and Vemurafenib 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; Vemurafenib belongs to Oncology.
Why it happens
Additive QT prolongation plus CYP3A4 induction by vemurafenib.
What to do
Avoid if possible. If used together, monitor ECG and electrolytes and watch for reduced lapatinib effect.
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 Vemurafenib
Frequently asked questions
Can I take Lapatinib with Vemurafenib?
MediHelp rates the interaction as major. Lapatinib and Vemurafenib 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 drugs prolong the QT interval, and vemurafenib is a CYP3A4 inducer that may lower lapatinib exposure. Arrhythmia risk is increased, and lapatinib efficacy may be reduced.
How serious is the interaction between Lapatinib and Vemurafenib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible. If used together, monitor ECG and electrolytes and watch for reduced lapatinib effect.
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.
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