Posaconazole and Entrectinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Posaconazole
Entrectinib
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 posaconazole exposure, an increased CYP3A4 substrate exposure and an increased risk of QT interval prolongation and torsade de pointes
Interaction Deep Dive
Coadministration of posaconazole with QT prolonging P-gp inhibitors that are CYP3A4 substrates is contraindicated. Concomitant use may increase both posaconazole and CYP3A4 substrates exposure which may increase the risk of QT interval prolongation and torsade de pointes123.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of posaconazole; inhibition of CYP3A4-mediated metabolism by posaconazole; additive QT interval prolongation
Common questions
Can I take Posaconazole and Entrectinib together?
Increased posaconazole exposure, an increased CYP3A4 substrate exposure and an increased risk of QT interval prolongation and torsade de pointes Always confirm with your pharmacist or prescriber before making any change.
How serious is the Posaconazole and Entrectinib 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 Posaconazole or Entrectinib 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: NOXAFIL® PowderMix delayed-release oral suspension, posaconazole delayed-release oral suspension. Merck Sharp & Dohme LLC (per FDA), Rahway, NJ, 2026. DailyMed
- Product Information: NOXAFIL® intravenous injection, oral delayed-release tablets, oral suspension, posaconazole intravenous injection, oral delayed-release tablets, oral suspension. Merck Sharp & Dohme LLC (per FDA), Rahway, NJ, 2026. DailyMed
- Product Information: Posaconazole oral delayed-release tablets, posaconazole oral delayed-release tablets. SpecGx LLC (per DailyMed), Webster Groves, MO, 2024. DailyMed
Keep reading about Posaconazole
Keep reading about Entrectinib
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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