Drug interactions
Dexamethasone + Lapatinib
Severity: Moderate
Dexamethasone and Lapatinib: 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 substrate and a weak inhibitor of CYP3A4 and P-glycoprotein, whereas dexamethasone is a CYP3A4 substrate and inducer. Dexamethasone can lower lapatinib exposure, and lapatinib may modestly raise dexamethasone levels.
What this interaction means in plain words
Dexamethasone and Lapatinib 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.
Dexamethasone belongs to Endocrine; Lapatinib belongs to Oncology.
Why it happens
Dexamethasone induces CYP3A4, reducing lapatinib exposure, while lapatinib weakly inhibits CYP3A4 and P-glycoprotein.
What to do
Avoid prolonged systemic dexamethasone when alternatives exist, since lapatinib labeling advises avoiding strong inducers. Monitor lapatinib efficacy and steroid adverse effects.
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 Dexamethasone
- Bcg vaccine live + Dexamethasone Contraindicated
- Dexamethasone + Mifepristone Contraindicated
- Dexamethasone + Rilpivirine Contraindicated
- Dexamethasone + Smallpox vaccine live Contraindicated
- Dexamethasone + Varicella virus vaccine live Contraindicated
- Dexamethasone + Yellow fever vaccine Contraindicated
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Frequently asked questions
Can I take Dexamethasone with Lapatinib?
MediHelp rates the interaction as moderate. Dexamethasone and Lapatinib 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 substrate and a weak inhibitor of CYP3A4 and P-glycoprotein, whereas dexamethasone is a CYP3A4 substrate and inducer. Dexamethasone can lower lapatinib exposure, and lapatinib may modestly raise dexamethasone levels.
How serious is the interaction between Dexamethasone and Lapatinib?
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 prolonged systemic dexamethasone when alternatives exist, since lapatinib labeling advises avoiding strong inducers. Monitor lapatinib efficacy and steroid adverse effects.
What other medicines interact with Dexamethasone?
MediHelp also lists interactions of Dexamethasone with, for example, Bcg vaccine live, Mifepristone, Rilpivirine. The full list is on the Dexamethasone page.
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