Drug interactions
Darunavir + Lapatinib
Severity: Major
Darunavir and Lapatinib: 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
Darunavir, usually given with a booster, inhibits CYP3A4 and can markedly increase lapatinib exposure. This raises the risk of QT prolongation, hepatotoxicity and diarrhea.
What this interaction means in plain words
Darunavir and Lapatinib 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.
Darunavir belongs to Anti Virals; Lapatinib belongs to Oncology.
Why it happens
Inhibition of CYP3A4 by darunavir and its pharmacokinetic booster reduces lapatinib clearance.
What to do
Avoid if possible and choose an alternative antiretroviral. If necessary, reduce the lapatinib dose per labeling for strong CYP3A4 inhibitors and monitor ECG and liver function.
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 Darunavir
- Alfuzosin + Darunavir Contraindicated
- Avanafil + Darunavir Contraindicated
- Darunavir + Dronedarone Contraindicated
- Darunavir + Eletriptan Contraindicated
- Darunavir + Ergotamine Contraindicated
- Darunavir + Flibanserin Contraindicated
Frequently asked questions
Can I take Darunavir with Lapatinib?
MediHelp rates the interaction as major. Darunavir and Lapatinib 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. Darunavir, usually given with a booster, inhibits CYP3A4 and can markedly increase lapatinib exposure. This raises the risk of QT prolongation, hepatotoxicity and diarrhea.
How serious is the interaction between Darunavir and Lapatinib?
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 and choose an alternative antiretroviral. If necessary, reduce the lapatinib dose per labeling for strong CYP3A4 inhibitors and monitor ECG and liver function.
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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