Drug Interaction Report

Quinidine and Enasidenib: Interaction Details

A pharmacist-reviewed analysis of the Quinidine and Enasidenib 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

Enasidenib

Idhifa Idhifa®
+

Quinidine

Cardioquin® Cin-Quin® Duraquin® Quinact® Quinaglute® Quinalan® Quinatime® Quinidex®
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
Major
Potentially serious — often needs a change or close monitoring.
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 91 documented Quinidine interactions, 80 are rated major — 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
probable
Severity
Major

What happens

Reduced CYP3A substrate exposure and reduced efficacy of CYP3A substrate

Interaction Deep Dive

Avoid concomitant use of enasidenib (a CYP3A4 inducer) and a CYP3A substrate with NTI. Enasidenib decreases the exposure of CYP3A substrates, where minimal concentration changes may lead to reduced efficacy. In the drug interaction studies, midazolam (a sensitive CYP3A substrate) AUC (0 to inf) and Cmax decreased by 43% and 23%, respectively, following concomitant use of multiple doses of enasidenib 100 mg with a single intravenous dose of midazolam 0.03 mg/kg1.

Why it happens (mechanism)

Induction of CYP3A-substrate metabolism by enasidenib

Literature reports

1 report — tap to read

a) In the drug interaction studies, midazolam (a sensitive CYP3A substrate) AUC (0 to inf) and Cmax decreased by 43% and 23%, respectively, following concomitant use of multiple doses of enasidenib 100 mg with a single intravenous dose of midazolam 0.03 mg/kg. The decrease in midazolam exposure following oral administration of midazolam is expected to be larger than that following intravenous administration of midazolam. This is due to induction of CYP3A4 first pass metabolism by enasidenib and the reduced bioavailability of the midazolam oral formulation compared to the midazolam intravenous formulation 1.

Common questions

Can I take Quinidine and Enasidenib together?

Reduced CYP3A substrate exposure and reduced efficacy of CYP3A substrate Always confirm with your pharmacist or prescriber before making any change.

How serious is the Quinidine and Enasidenib 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 Quinidine or Enasidenib 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 (1)

  1. Product Information: IDHIFA(R) oral tablets, enasidenib oral tablets. Bristol-Myers Squibb (per FDA), Princeton, NJ, 2023. DailyMed
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Enasidenib

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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:

Enasidenib + Activated Charcoal Grapefruit St. John's Wort 1,3-dmaa Acacia Rigidula Active Hexose Correlated Compound (ahcc) Adrafinil African Wild Potato + 195 more
Quinidine + Activated Charcoal American Hellebore Arsenic Beer Cesium Cinchona Ephedra Grapefruit + 199 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.