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Drug interactions

Crizotinib + Ketoconazole

Severity: Major

Crizotinib and Ketoconazole: major interaction.

Last updated Sources: US FDA label

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 increases crizotinib exposure, raising the risk of hepatotoxicity, QT prolongation and bradycardia.

What this interaction means in plain words

Crizotinib 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.

Crizotinib belongs to Oncology; Ketoconazole belongs to Anti Fungals.

Evidence level: High

Why it happens

Ketoconazole is a strong CYP3A4 inhibitor that reduces crizotinib clearance.

What to do

Avoid strong CYP3A4 inhibitors with crizotinib. If unavoidable, reduce the crizotinib dose per labeling 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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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References

Frequently asked questions

Can I take Crizotinib with Ketoconazole?

MediHelp rates the interaction as major. Crizotinib 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 increases crizotinib exposure, raising the risk of hepatotoxicity, QT prolongation and bradycardia.

How serious is the interaction between Crizotinib 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 strong CYP3A4 inhibitors with crizotinib. If unavoidable, reduce the crizotinib dose per labeling and monitor ECG, electrolytes and liver tests.

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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