Drug interactions
Ketoconazole + Quizartinib
Severity: Major
Ketoconazole and Quizartinib: 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
Ketoconazole increases quizartinib exposure, which raises the risk of QT prolongation and torsades de pointes. Ketoconazole itself can prolong QT, which adds to the risk.
What this interaction means in plain words
Ketoconazole and Quizartinib 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 belongs to Anti Fungals; Quizartinib belongs to Oncology.
Why it happens
Strong CYP3A4 inhibition reduces quizartinib clearance, with additive QT effects.
What to do
Reduce quizartinib dose per labeling during strong CYP3A inhibitor use and monitor ECG and electrolytes.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Other interactions of Quizartinib
- Quizartinib + Thioridazine Contraindicated
- Quizartinib + Ziprasidone Contraindicated
- Alfuzosin + Quizartinib Major
- Amiodarone + Quizartinib Major
- Amitriptyline + Quizartinib Major
- Amobarbital + Quizartinib Major
Frequently asked questions
Can I take Ketoconazole with Quizartinib?
MediHelp rates the interaction as major. Ketoconazole and Quizartinib 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 increases quizartinib exposure, which raises the risk of QT prolongation and torsades de pointes. Ketoconazole itself can prolong QT, which adds to the risk.
How serious is the interaction between Ketoconazole and Quizartinib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce quizartinib dose per labeling during strong CYP3A inhibitor use and monitor ECG and electrolytes.
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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