Drug Interaction Report

Ketoconazole Topical and Gilteritinib: Interaction Details

A pharmacist-reviewed analysis of the Ketoconazole Topical and Gilteritinib interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Ketoconazole Topical

Extina® Foam Ketozole® Cream Kuric Nizoral AD® Shampoo Nizoral® Cream Nizoral® Shampoo Xolegel®
+

Gilteritinib

Xospata Xospata®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 546 documented Ketoconazole Topical interactions, 380 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

Increased gilteritinib exposure

Interaction Deep Dive

Concomitant use of gilteritinib (substrate of CYP3A and P-gp) with ketoconazole ( strong CYP3A and P-gp inhibitor) may increase gilteritinib exposure12. Consider alternative therapies that do not include a strong CYP3A inhibitor. If concomitant use is essential, monitor the patient more frequently for gilteritinib-associated adverse events and interrupt and reduce the gilteritinib dosage in patients with serious or life-threatening toxicity 2.

Why it happens (mechanism)

Inhibition of CYP3A-mediated metabolism of gilteritinib; inhibition of P-gp-mediated efflux transport of gilteritinib

Literature reports

1 report — tap to read

a) Concomitant use of gilteritinib with itraconazole (a strong CYP3A inhibitor) increased gilteritinib Cmax by approximately 20% and increased the AUC approximately 120% 2.

Common questions

Can I take Ketoconazole Topical and Gilteritinib together?

Increased gilteritinib exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Ketoconazole Topical and Gilteritinib interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Ketoconazole Topical or Gilteritinib need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there a safer alternative to one of these medications for me?

References (2)

  1. Product Information: Ketoconazole oral tablet, ketoconazole oral tablet. Taro Pharmaceuticals U.S.A. Inc. (per DailyMed), Hawthorne, NY, 2024. DailyMed
  2. Product Information: XOSPATA(R) oral tablets, gilteritinib oral tablets. Astellas Pharma US Inc (per FDA), Northbrook, IL, 2022. DailyMed
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Ketoconazole Topical

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Gilteritinib

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All Gilteritinib interactions (82) Gilteritinib drug information
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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.