Abrocitinib and Fluconazole: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fluconazole
Abrocitinib
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.
Fluconazole (Diflucan) is an antifungal, and abrocitinib (Cibinqo) is a pill for eczema. Your body normally breaks down abrocitinib using certain liver enzymes. Fluconazole slows those enzymes down, so more abrocitinib and its active form stay in your body. In studies, that raised abrocitinib levels by roughly two to almost five times.
Higher levels can mean more side effects, like nausea, headache, low blood counts, or a higher chance of infection. The good news is your care team knows about this and can plan around it. Don't stop or change either medicine on your own. Just talk with your pharmacist or doctor so they can pick the safest option for you.
Effect: Fluconazole inhibits CYP2C19 (strong), CYP2C9 (moderate), and CYP3A4, reducing metabolism of abrocitinib and its active metabolites, increasing exposure.
- Magnitude: Combined active-moiety AUC ~2.5-fold higher (abrocitinib alone AUC ~4.8-fold); Cmax +23%, AUC +155%.
- Direction: Increased abrocitinib exposure and effect (neither drug is a prodrug requiring activation).
- Evidence/severity: Probable, major.
- Management: Avoid concomitant use per labeling. Monitor for dose-related toxicity (cytopenias, infection, GI effects) if exposure occurs; consider an alternative antifungal without this inhibition profile.
What happens
Increased abrocitinib exposure and an increased active metabolite exposure
Interaction Deep Dive
When abrocitinib is given together with moderate or strong CYP2C19 inhibitors, as well as agents that moderately inhibit both CYP3A4 and CYP2C9, the exposure of abrocitinib and its active metabolites may rise, potentially heightening the risk of adverse events. In the case of fluconazole, which strongly inhibits CYP2C19 and moderately inhibits CYP2C9, combining it with abrocitinib produced a 23% rise in Cmax alongside a 155% rise in AUC for abrocitinib and its active metabolites1. With fluconazole (an inhibitor of CYP2C9, CYP2C19, and CYP3A4), the systemic exposure (AUC) of abrocitinib was roughly 4.8-fold greater, and the combined exposure (AUC) of abrocitinib together with its active metabolites was roughly 2.5-fold greater, relative to abrocitinib given by itself 23. Concurrent use of abrocitinib with moderate or strong inhibitors of both CYP2C19 and CYP2C9, such as fluconazole, should be avoided 231.
Why it happens (mechanism)
Inhibition of CYP2C9-mediated metabolism of abrocitinib; inhibition of CYP3A4-mediated metabolism of abrocitinib; inhibition of CYP2C19-mediated metabolism of abrocitinib
How to manage this interaction
Because fluconazole can push abrocitinib levels well above normal, product labeling recommends avoiding this combination. Here is what typically happens:
- Your care team may choose a different antifungal that does not block these liver enzymes, or find another way to treat the infection.
- If both are truly needed, they may monitor you more closely for side effects such as low blood counts, infections, nausea, or headache.
What to do: Keep taking your medicines as prescribed and do not stop either on your own. Let your pharmacist or prescriber know you take abrocitinib before starting fluconazole so they can pick the safest plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) When abrocitinib 100 mg was given together with fluconazole (a strong CYP2C19 inhibitor and moderate inhibitor of CYP2C9 and CYP3A) at 400 mg on day 1 followed by 200 mg on days 2 through 7, the Cmax and AUC(infinity) of abrocitinib and its metabolites M1 and M2 rose by 1.23-fold and 2.55-fold, respectively 1.
b) In drug interaction studies, coadministration with fluconazole (an inhibitor of CYP2C9, CYP2C19, and CYP3A4) resulted in the systemic exposure (AUC) of abrocitinib being roughly 4.8-fold greater, and the combined exposure (AUC) of abrocitinib together with its active metabolites being roughly 2.5-fold greater, relative to abrocitinib given by itself 23.
Common questions
Can I take Abrocitinib and Fluconazole together?
Fluconazole raises abrocitinib levels a lot and this combination is generally avoided; talk to your pharmacist or doctor so they can choose a safer option or monitor you closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abrocitinib and Fluconazole 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 is the Abrocitinib and Fluconazole interaction managed?
Because fluconazole can push abrocitinib levels well above normal, product labeling recommends avoiding this combination. Here is what typically happens: Your care team may choose a different antifungal that does not block these liver enzymes, or find another way to treat the infection. If both are truly needed, they may monitor you more closely for side effects such as low blood counts, infection… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Abrocitinib or Fluconazole 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 (3)
- Product Information: CIBINQO(TM) oral tablets, abrocitinib oral tablets. Pfizer Labs (per FDA), New York, NY, 2022. DailyMed
- 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
Keep reading about Fluconazole
Keep reading about Abrocitinib
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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