Fluconazole and Glasdegib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fluconazole
Glasdegib
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 CYP3A4 substrate exposure and an increased risk of QT interval prolongation
Interaction Deep Dive
Fluconazole is a moderate CYP3A4 inhibitor that may cause QT interval prolongation and torsade de pointes. Coadministration of fluconazole with CYP3A4 substrates that are known to prolong the QT interval is contraindicated as it may increase CYP3A4 substrates exposure. Fluconazole-mediated CYP3A4 inhibition may continue for 4 to 5 days after discontinuation because of the long half-life12.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by fluconazole; additive QT interval prolongation
Literature reports
1 report — tap to read
Common questions
Can I take Fluconazole and Glasdegib together?
Increased CYP3A4 substrate exposure and an increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fluconazole and Glasdegib 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Fluconazole or Glasdegib 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 (4)
- Product Information: DIFLUCAN(R) oral tablets, suspension, fluconazole oral tablets, suspension. Roerig (per FDA), New York, NY, 2024. DailyMed
- Product Information: DIFLUCAN(R) intravenous injection, fluconazole intravenous injection. Roerig (per FDA), New York, NY, 2024. DailyMed
- Khazan M & Mathis AS: Probable cause of torsades de pointes induced by fluconazole. Pharmacotherapy 2002; 22(12):1632-1637.
- Wassmann S, Nickenig G, & Bohm M: Long QT syndrome and torsade de pointes in a patient receiving fluconazole. Ann Intern Med 1999; 131:797. PubMed
Keep reading about Fluconazole
Keep reading about Glasdegib
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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