Drug Interaction Report

Encorafenib and Posaconazole: Interaction Details

A pharmacist-reviewed analysis of the Encorafenib and Posaconazole interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Posaconazole

Noxafil
+

Encorafenib

Braftovi Braftovi®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Contraindicated
These should generally not be used together.
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.

Of 468 documented Encorafenib interactions, 36 are rated contraindicated — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Contraindicated

What happens

Increased CYP3A4 substrate exposure and an increased risk of QT interval prolongation

Interaction Deep Dive

Posaconazole is a strong CYP3A4 inhibitor and is independently capable of prolonging the QT interval. Cases of torsade de pointes have been reported with the use of posaconazole. Use of posaconazole with CYP3A4 substrates that also prolong the QT interval is contraindicated, as concomitant use may lead to increased exposure to the CYP3A4 substrate and increased risk of QT interval prolongation and torsade de pointes123.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated metabolism by posaconazole; additive QT interval prolongation

Literature reports

1 report — tap to read

a) Cases of torsade de pointes have been reported with the use of posaconazole 123.

Common questions

Can I take Encorafenib and Posaconazole 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 Encorafenib and Posaconazole 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 Encorafenib or Posaconazole 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)

  1. Product Information: NOXAFIL® PowderMix delayed-release oral suspension, posaconazole delayed-release oral suspension. Merck Sharp & Dohme LLC (per FDA), Rahway, NJ, 2026. DailyMed
  2. 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
  3. Product Information: Posaconazole oral delayed-release tablets, posaconazole oral delayed-release tablets. SpecGx LLC (per DailyMed), Webster Groves, MO, 2024. DailyMed
Was this write-up helpful?
Posaconazole

Keep reading about Posaconazole

All Posaconazole interactions (166)
Also serious with: Atorvastatin Fluvastatin Entrectinib Alfuzosin
Encorafenib

Keep reading about Encorafenib

All Encorafenib interactions (468) Encorafenib drug information
Also serious with: Piperaquine Atazanavir Pimozide Doravirine
Beyond drug–drug

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:

Posaconazole + Activated Charcoal Coffee Charcoal European Mandrake Glucomannan Guar Gum Gum Arabic Slippery Elm Tragacanth + 9 more
Encorafenib + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia St. John's Wort + 143 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.