Drug Interaction Report

Cholestyramine and Digoxin: Interaction Details

A pharmacist-reviewed analysis of the Cholestyramine and Digoxin 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

Cholestyramine

Prevalite Questran
+

Digoxin

Cardoxin® Digitek Digitek® Digox Lanoxicaps® Lanoxin Lanoxin®
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 40 documented Cholestyramine interactions, 5 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
rapid
Evidence
probable
Severity
Major

What happens

Reduced digoxin exposure

Interaction Deep Dive

Coadministration of digoxin and cholestyramine reduce digoxin exposure123. Measure digoxin exposure prior to initiation of concurrent use. Increase the digoxin dose by approximately 20% to 40%, if necessary, and continue monitoring digoxin exposure 12.

Why it happens (mechanism)

Reduced digoxin absorption

Literature reports

1 report — tap to read

a) Concomitant digoxin and cholestyramine therapy has resulted in impaired absorption of digoxin 45. In a cross-over study involving six healthy volunteers, cholestyramine 8 g administered immediately after digoxin 0.25 mg resulted in a decrease in the digoxin absorption by 30% to 40%. Maximum concentration (Cmax) decreased from 1.1 mcg/L to 0.7 mcg/L, and the area under the concentration-time curve (AUC) of digoxin decreased from 14.3 mcg/L/h to 8.6 mcg/L/h 3.

Common questions

Can I take Cholestyramine and Digoxin together?

Reduced digoxin exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Cholestyramine and Digoxin interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.

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 Cholestyramine or Digoxin 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)

  1. Product Information: LANOXIN(R) oral tablets, digoxin oral tablets. Concordia Pharmaceuticals Inc (per FDA), Kansas City, MO, 2019. DailyMed
  2. Product Information: DIGOXIN oral tablets, digoxin oral tablets. Aurobindo Pharma USA, Inc. (per Dailymed), East Windsor, NJ, May. DailyMed
  3. Neuvonen PJ, Kivisto K, & Hirvisalo EL: Effects of resins and activated charcoal on the absorption of digoxin, carbamazepine and frusemide. Br J Clin Pharmacol 1988; 25:229-233. DOI
  4. Hall WH, Shappell SD, & Doherty JE: The effect of cholestyramine on digoxin absorption and excretion in man. Am J Cardiol 1977; 39:213-216. PubMed
  5. Brown DD, Juhl RP, Warner SL, et al: Decreased bioavailability of digoxin due to hypocholesterolemic interventions. Circulation 1978; 58(1):164-72. DOI
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Cholestyramine

Keep reading about Cholestyramine

All Cholestyramine interactions (40)
Also serious with: Deferasirox Dexamethasone Injection Dexamethasone Ophthalmic Ezetimibe
Digoxin

Keep reading about Digoxin

All Digoxin interactions (453) Digoxin drug information
Also serious with: Levoketoconazole Meclofenamate Mavorixafor Parathyroid Hormone Injection
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:

Cholestyramine + Activated Charcoal Coffee Charcoal European Mandrake Glucomannan Guar Gum Gum Arabic Niacin Slippery Elm + 11 more
Digoxin + Activated Charcoal Aloe Blue Flag Danshen European Buckthorn Foxglove Indian Snakeroot Lily-of-the-valley + 105 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.