Ivacaftor and Ketoconazole Topical: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ivacaftor
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 ivacaftor exposure
Interaction Deep Dive
Concomitant administration of ivacaftor with strong CYP3A4 inhibitors may increase ivacaftor exposure. For Kalydeco®, reduce dose to 150 mg twice weekly (6 years or older), or 25 mg (wt, 5 kg to less than 7 kg), 50 mg (7 kg to less than 14 kg) or 75 mg (14 kg or greater) of oral granules twice weekly in patients 6 months to 6 years; concomitant use is not recommended in patients less than 6 months2. For Orkambi®, give lumacaftor 100 mg/ivacaftor 125 mg (6 to 11 years) or lumacaftor 200 mg/ivacaftor 125 mg (12 years or older) once daily for first week, then continue the usual dose 3. For Symdeko™, give tezacaftor 100 mg/ivacaftor 150 mg 4, for Trikafta™, give 2 tablets (elexacaftor 100 mg/tezacaftor 50 mg/ivacaftor 75 mg per tablet) orally in the morning on day 1 and 4 then continue this dose twice weekly 1. Use of lumacaftor/ivacaftor is not recommended 2 weeks before, during and 2 weeks after itraconazole treatment 5.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism of ivacaftor
Literature reports
2 reports — tap to read
a) Coadministration of a single dose of ivacaftor 150 mg with strong CYP3A inhibitor ketoconazole 400 mg daily significantly increased ivacaftor AUC by 8.45-fold and Cmax by 2.65-fold 1.
b) Coadministration of tezacaftor 25 mg and ivacaftor 50 mg orally once daily with strong CYP3A inhibitor itraconazole 200 mg orally twice daily on day 1, followed by 200 mg once daily increased ivacaftor exposure by 15.6-fold and Cmax by 8.6-fold 41.
Common questions
Can I take Ivacaftor and Ketoconazole Topical together?
Increased ivacaftor exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ivacaftor 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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Ivacaftor 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 (5)
- Product Information: TRIKAFTA(R) oral tablets oral granules, elexacaftor, tezacaftor, ivacaftor oral tablets oral granules; ivacaftor oral tablets oral granules. Vertex Pharmaceuticals Incorporated (per FDA), Boston, MA, 2024. DailyMed
- Product Information: KALYDECO(R) oral tablets, oral granules, ivacaftor oral tablets, oral granules. Vertex Pharmaceuticals Incorporated (per FDA), Boston, MA, 2023. DailyMed
- Product Information: ORKAMBI(R) oral tablets, lumacaftor ivacaftor oral tablets. Vertex Pharmaceuticals Incorporated (per manufacturer), Boston, MA, 2016. DailyMed
- Product Information: SYMDEKO(TM) oral tablets, tezacaftor ivacaftor oral tablets and ivacaftor oral tablets. Vertex Pharmaceuticals Incorporated (per manufacturer), Boston, MA, 2018. DailyMed
- Product Information: SPORANOX(R) oral capsules, itraconazole oral capsules. Janssen Pharmaceuticals Inc (per FDA), Titusville, NJ, 2022. DailyMed
Keep reading about Ivacaftor
Keep reading about Ketoconazole Topical
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:
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