Drug interactions
Lapatinib + Selumetinib
Severity: Moderate
Lapatinib and Selumetinib: moderate 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 is a CYP3A4 inhibitor that may increase selumetinib exposure. This can intensify selumetinib toxicities such as gastrointestinal effects, rash and cardiomyopathy.
What this interaction means in plain words
Lapatinib and Selumetinib can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Lapatinib belongs to Oncology; Selumetinib belongs to Oncology.
Why it happens
Inhibition of CYP3A4 metabolism of selumetinib.
What to do
Avoid if possible. If unavoidable, reduce the selumetinib dose per labeling and monitor for toxicity.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Selumetinib
Frequently asked questions
Can I take Lapatinib with Selumetinib?
MediHelp rates the interaction as moderate. Lapatinib and Selumetinib can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Lapatinib is a CYP3A4 inhibitor that may increase selumetinib exposure. This can intensify selumetinib toxicities such as gastrointestinal effects, rash and cardiomyopathy.
How serious is the interaction between Lapatinib and Selumetinib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible. If unavoidable, reduce the selumetinib dose per labeling and monitor for toxicity.
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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