Drug interactions
Entrectinib + Ketoconazole
Severity: Major
Entrectinib and Ketoconazole: major interaction.
Last updated Sources: UK SmPC
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
Ketoconazole markedly raises entrectinib exposure, increasing the risk of QT prolongation, heart failure, CNS effects and other toxicities.
What this interaction means in plain words
Entrectinib and Ketoconazole 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.
Entrectinib belongs to Oncology; Ketoconazole belongs to Anti Fungals.
Why it happens
Ketoconazole inhibits CYP3A4, the major pathway for entrectinib metabolism.
What to do
Avoid the combination; if it is necessary, reduce the entrectinib dose per labeling and monitor ECG. Return to the usual dose after the inhibitor has been stopped for several half-lives.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Other interactions of Entrectinib
Frequently asked questions
Can I take Entrectinib with Ketoconazole?
MediHelp rates the interaction as major. Entrectinib and Ketoconazole 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. Ketoconazole markedly raises entrectinib exposure, increasing the risk of QT prolongation, heart failure, CNS effects and other toxicities.
How serious is the interaction between Entrectinib and Ketoconazole?
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 it is necessary, reduce the entrectinib dose per labeling and monitor ECG. Return to the usual dose after the inhibitor has been stopped for several half-lives.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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