Pexidartinib and Ketoconazole Topical: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ketoconazole Topical
Pexidartinib
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.
What happens
Increased pexidartinib exposure; hepatotoxicity
Interaction Deep Dive
The concomitant use of pexidartinib (CYP3A4 substrate) with a strong CYP3A inhibitor may increase pexidartinib exposure and should be avoided. Pexidartinib coadministered with itraconazole (a strong CYP3A inhibitor) resulted in a 70% increase in mean pexidartinib AUC and a 48% increase in pexidartinib Cmax. If coadministration is required, reduce pexidartinib dose based on planned total daily dose: from 800 or 600 mg/day to 200 mg twice daily; from 400 mg/day to 200 mg once daily. If the CYP3A inhibitor is discontinued, return to previous pexidartinib dose after 3 plasma half-lives of the CYP3A inhibitor have passed. Additionally, pexidartinib can cause serious and potentially fatal liver injury; hepatotoxicity with ductopenia and cholestasis occurred during clinical trials with pexidartinib. The mechanism is unknown and occurrence is not predictable. Avoid coadministration with other drugs known to cause hepatotoxicity in patients with increased (greater than ULN) serum transaminases, total bilirubin, or direct bilirubin or active liver or biliary tract disease1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of pexidartinib; additive risk for hepatotoxicity
Literature reports
1 report — tap to read
a) Pexidartinib coadministered with itraconazole (another strong CYP3A inhibitor) resulted in a 70% increase in mean pexidartinib AUC and a 48% increase in pexidartinib Cmax 1.
Common questions
Can I take Pexidartinib and Ketoconazole Topical together?
Increased pexidartinib exposure; hepatotoxicity Always confirm with your pharmacist or prescriber before making any change.
How serious is the Pexidartinib and Ketoconazole Topical 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 Pexidartinib or Ketoconazole Topical 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 (1)
- Product Information: TURALIO(TM) oral capsules, pexidartinib oral capsules. Daiichi Sankyo Inc (per FDA), Basking Ridge, NJ, 2019. DailyMed
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