Deflazacort and Voriconazole: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Voriconazole
Deflazacort
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 exposure to active metabolite of deflazacort, an increased risk of Cushing’s syndrome and an increased risk of adrenal dysfunction
Interaction Deep Dive
Coadministration of deflazacort with CYP3A4 inhibitors, such as voriconazole may increase exposure to the active metabolite of deflazacort, 21-desDFZ, which is a CYP3A4 substrate. When coadministration is necessary, administer one-third the usual dosage of deflazacort; for example, a dose of 36 mg/day would be reduced to 12 mg/day1. Concomitant use of voriconazole with deflazacort (corticosteroid) may also cause adrenal suppression due to voriconazole associated CYP3A4 inhibition of their metabolism. Cushing’s syndrome with and without subsequent adrenal insufficiency has also been reported in patients receiving voriconazole concomitantly with corticosteroids. Monitor patients receiving voriconazole and corticosteroids (via all routes of administration) for adrenal dysfunction, both during and after voriconazole treatment. Instruct patients to seek immediate medical care if they develop signs and symptoms of Cushing’s syndrome or adrenal insufficiency 2.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of active metabolite of deflazacort; direct inhibition of steroidogenesis by azoles
Literature reports
1 report — tap to read
a) Deflazacort administered following multiple doses of clarithromycin (a strong CYP3A4 and P-gp inhibitor) increased geometric mean exposure to the deflazacort active metabolite, 21-desDFZ, by 2.3- to 3.4-fold compared with deflazacort alone 1.
Common questions
Can I take Deflazacort and Voriconazole together?
Increased exposure to active metabolite of deflazacort, an increased risk of Cushing’s syndrome and an increased risk of adrenal dysfunction Always confirm with your pharmacist or prescriber before making any change.
How serious is the Deflazacort and Voriconazole 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 Deflazacort or Voriconazole 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: EMFLAZA(TM) oral tablets, suspension, deflazacort oral tablets, suspension. Marathon Pharmaceuticals LLC (per FDA), Northbrook, IL, 2017. DailyMed
- Product Information: VFEND(R) oral tablets, oral suspension, intravenous injection, voriconazole oral tablets, oral suspension, intravenous injection. Roerig (per FDA), New York, NY, 2025. DailyMed
Keep reading about Voriconazole
Keep reading about Deflazacort
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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