Drug interactions
Lapatinib + Quercetin
Severity: Minor
Lapatinib and Quercetin: minor 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
Quercetin is a dietary flavonoid with variable effects on P-gp and CYP enzymes. Any change in lapatinib exposure from supplements is uncertain and unlikely to be large.
What this interaction means in plain words
Lapatinib and Quercetin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Variable modulation of P-gp and CYP3A4 by quercetin; the net effect on lapatinib is not well established.
What to do
Advise patients to avoid high-dose quercetin supplements during lapatinib therapy and monitor for changes in response or toxicity.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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
Frequently asked questions
Can I take Lapatinib with Quercetin?
MediHelp rates the interaction as minor. Lapatinib and Quercetin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Quercetin is a dietary flavonoid with variable effects on P-gp and CYP enzymes. Any change in lapatinib exposure from supplements is uncertain and unlikely to be large.
How serious is the interaction between Lapatinib and Quercetin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid high-dose quercetin supplements during lapatinib therapy and monitor for changes in response or 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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