Drug interactions
Lapatinib + Levoketoconazole
Severity: Major
Lapatinib and Levoketoconazole: 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
Levoketoconazole is a strong CYP3A4 inhibitor and markedly increases lapatinib concentrations. This raises the risk of lapatinib toxicity, including QT prolongation and hepatotoxicity. Levoketoconazole itself also prolongs the QT interval.
What this interaction means in plain words
Lapatinib and Levoketoconazole 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.
Lapatinib belongs to Oncology; Levoketoconazole belongs to Endocrine.
Why it happens
Strong CYP3A4 inhibition reduces lapatinib clearance; additive QT effects also contribute.
What to do
Avoid the combination. If unavoidable, reduce the lapatinib dose according to labeling 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 Levoketoconazole
- Alfuzosin + Levoketoconazole Contraindicated
- Alprazolam + Levoketoconazole Contraindicated
- Amiodarone + Levoketoconazole Contraindicated
- Avanafil + Levoketoconazole Contraindicated
- Cisapride + Levoketoconazole Contraindicated
- Clarithromycin + Levoketoconazole Contraindicated
Frequently asked questions
Can I take Lapatinib with Levoketoconazole?
MediHelp rates the interaction as major. Lapatinib and Levoketoconazole 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. Levoketoconazole is a strong CYP3A4 inhibitor and markedly increases lapatinib concentrations. This raises the risk of lapatinib toxicity, including QT prolongation and hepatotoxicity. Levoketoconazole itself also prolongs the QT interval.
How serious is the interaction between Lapatinib and Levoketoconazole?
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 the combination. If unavoidable, reduce the lapatinib dose according to labeling 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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