Ceritinib and Ketoconazole Topical: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ceritinib
Ketoconazole Topical
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 ceritinib exposure, increased ketoconazole exposure and an increased risk of QT interval prolongation
Interaction Deep Dive
Coadministration of ketoconazole (a strong CYP3A4 inhibitor that may prolong the QT interval) with CYP3A4 substrates that are known to prolong the QT interval, such as ceritinib is contraindicated as it may cause increased ceritinib exposure, increasing the risk for QT interval prolongation and result in life-threatening ventricular tachyarrhythmias such as torsade de pointes1. Concomitant use of ketoconazole (CYP3A4 substrate) with ceritinib (CYP3A4 inhibitor) may also increase ketoconazole exposure. If coadministration cannot be avoided, consider dose reductions of the ketoconazole and reduce the ceritinib dose by approximately one-third (rounded to the nearest 150 mg dosage strength). Resume regular ceritinib dosing upon discontinuation of ketoconazole 2.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of ketoconazole; inhibition of CYP3A4-substrate metabolism of ceritinib; additive QT interval prolongation
Literature reports
1 report — tap to read
a) Coadministration of a single dose of ceritinib 450 mg and ketoconazole 200 mg twice daily for 14 days resulted in a 2.9-fold increase in ceritinib AUC and a 22% increase in ceritinib Cmax in a study of 19 healthy subjects 2.
Common questions
Can I take Ceritinib and Ketoconazole Topical together?
Increased ceritinib exposure, increased ketoconazole exposure and an increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ceritinib and Ketoconazole Topical interaction?
It is rated contraindicated. These should generally not be used together.
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 Ceritinib 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 (2)
- Product Information: Ketoconazole oral tablet, ketoconazole oral tablet. Taro Pharmaceuticals U.S.A. Inc. (per DailyMed), Hawthorne, NY, 2024. DailyMed
- Product Information: ZYKADIA(R) oral capsules, oral tablets, ceritinib oral capsules, oral tablets. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2019. DailyMed
Keep reading about Ceritinib
Keep reading about Ketoconazole Topical
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