Drug interactions
Erythromycin lactobionate + Lapatinib
Severity: Major
Erythromycin lactobionate and Lapatinib: major interaction.
Last updated Sources: Health Canada product monograph
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
Intravenous erythromycin inhibits CYP3A4 and can increase lapatinib exposure, with risk of hepatotoxicity, diarrhea and QT prolongation. Both drugs prolong QT, adding arrhythmic risk.
What this interaction means in plain words
Erythromycin lactobionate 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.
Erythromycin lactobionate belongs to Anti Bacterial; Lapatinib belongs to Oncology.
Why it happens
Erythromycin inhibits CYP3A4 metabolism of lapatinib, with additive QT prolongation.
What to do
Use a non-macrolide antibiotic. If unavoidable, reduce the lapatinib dose and monitor ECG, electrolytes and liver tests.
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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References
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 Erythromycin lactobionate
- Cisapride + Erythromycin lactobionate Contraindicated
- Dihydroergotamine + Erythromycin lactobionate Contraindicated
- Dronedarone + Erythromycin lactobionate Contraindicated
- Eletriptan + Erythromycin lactobionate Contraindicated
- Ergotamine + Erythromycin lactobionate Contraindicated
- Erythromycin lactobionate + Flibanserin Contraindicated
Frequently asked questions
Can I take Erythromycin lactobionate with Lapatinib?
MediHelp rates the interaction as major. Erythromycin lactobionate 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. Intravenous erythromycin inhibits CYP3A4 and can increase lapatinib exposure, with risk of hepatotoxicity, diarrhea and QT prolongation. Both drugs prolong QT, adding arrhythmic risk.
How serious is the interaction between Erythromycin lactobionate 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: Use a non-macrolide antibiotic. If unavoidable, reduce the lapatinib dose and monitor ECG, electrolytes and liver tests.
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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