Digitoxin and Cholestyramine Resin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cholestyramine Resin
Digitoxin
No brand names on record
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
Decreased digitoxin effectiveness
Interaction Deep Dive
Cholestyramine can bind digitoxin in the gastrointestinal tract and alter its enterohepatic recycling, thereby altering the plasma level of digitoxin and its half-life46. Digitoxin toxicity has been successfully treated with cholestyramine 57.
Why it happens (mechanism)
Decreased digitoxin absorption
Literature reports
4 reports — tap to read
a) Ten patients were studied to examine the effects of cholestyramine and colestipol on digitalis therapy. Patients received 15 grams per day of colestipol, 12 grams per day of cholestyramine, or placebo 1.5 hours after the administration of either digoxin or digitoxin. Administration of colestipol or cholestyramine 1.5 hours after the cardiac glycoside, for long periods of time, was found to have no significant effect on serum cardiac glycoside levels compared to placebo 1.
b) Concomitant administration of digitoxin and cholestyramine can result in a reduction of digitoxin half-life from 11.5 days to 6.6 days, presumably by interruption of the enterohepatic circulation of digitoxin 2. Digitoxin toxicity has been treated with cholestyramine with some success 3.
c) The effects of cholestyramine and spironolactone on the elimination rate of digitoxin were studied in six healthy volunteers. Subjects received digitoxin 0.1 mg to 0.15 mg for 30 days until steady-state plasma digitoxin levels were achieved. On day 31, the subjects were randomized to four treatment phases in which they received cholestyramine 4 grams eight times per day and spironolactone 300 mg per day, or a matched placebo of either drug. Not all of the subjects completed the four treatment phases. Coadministration of cholestyramine with digitoxin resulted in a decrease in digitoxin half-life from 141.6 hours to 84.4 hours 4.
d) A 72-year old woman was admitted to the hospital complaining of anorexia, vomiting, weakness, visual disturbances, and heartbeat irregularities. The patient was taking digitoxin 0.2 mg four times daily and diazepam 5 mg three times daily in addition to aspirin as needed. On admission, the patient had a blood pressure was 100/56 mm Hg and an ECG showed marked atrioventricular block, short QT interval, and periods of sinus arrest. Digitoxin level was measured to be 92 ng/mL (normal range 15 to 26 ng/mL). Fifteen hours later, the digitoxin level continued to be high, at 89 ng/mL. After the patient was started on cholestyramine 4 grams every six hours, the decrease in serum digitoxin levels was notably enhanced. By the time that cholestyramine therapy was discontinued, which was approximately 165 hours after the last dose of digitoxin, the digitoxin level had dropped to 31.5 ng/mL. The patient began to note improvement in symptoms and the degree of atrioventricular block gradually decreased 5.
Common questions
Can I take Digitoxin and Cholestyramine Resin together?
Decreased digitoxin effectiveness Always confirm with your pharmacist or prescriber before making any change.
How serious is the Digitoxin and Cholestyramine Resin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
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 Digitoxin or Cholestyramine Resin 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 anything you'd monitor while I'm on both?
References (7)
- Bazzano G & Bazzano GS: Effect of digitalis-binding resins on cardiac glycoside plasma. Clin Res 1972; 20:24.
- Caldwell JH, Bush CA, & Greenberger NJ: Interruption of the enterohepatic circulation of digitoxin by cholestyramine. II. Effect on metabolic disposition of tritium-labeled digitoxin and cardiac systole intervals in man. J Clin Invest 1971; 50:2638-2644. DOI
- Bazzano G & Bazzano GS: Digitalis intoxication. Treatment with a new steroid-binding resin. JAMA 1972a; 220:828-830. DOI
- Carruthers SG & Dujovne CA: Cholestyramine and spironolactone and their combination in digitoxin elimination. Clin Pharmacol Ther 1980; 27:184-187. DOI
- Pieroni RE & Fisher JG: Use of cholestyramine resin in digitoxin toxicity. JAMA 1981; 245:1939-1940. DOI
- Baciewicz AM, Isaacson ML, & Lipscomb GL: Cholestyramine resin in the treatment of digitoxin toxicity. Drug Intell Clin Pharm 1983; 17:57-59. PubMed
- Bazzano G & Bazzano GS: Effect of digitalis-binding resins on cardiac glycoside plasma levels. JAMA 1972; 220:828-830.
Keep reading about Cholestyramine Resin
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