Dicumarol 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
Dicumarol
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 effects of dicumarol
Interaction Deep Dive
Cholestyramine has been shown to decrease absorption of oral anticoagulants. Separating the doses of the drugs by several hours may lessen the impact of this interaction but since dicumarol undergoes enterohepatic recirculation, time separation of the doses will not eliminate the problem123.
Why it happens (mechanism)
Decreased dicumarol absorption, interference with enterohepatic recycling
Common questions
Can I take Dicumarol and Cholestyramine Resin together?
Decreased effects of dicumarol Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dicumarol 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 Dicumarol 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 (3)
- Meinertz T, Gilfrich MJ, Groth U, et al: Interruption of the enterohepatic circulation of phenprocoumon by cholestyramine. Clin Pharmacol Ther 1977a; 21:731-735. PubMed
- Jahnchen E, Meinertz T, Gilfrich HJ, et al: Enhanced elimination of warfarin during treatment with cholestyramine. Br J Clin Pharmacol 1978; 5:437-440. DOI
- Meinertz T, Gilfrich MJ, Bork R, et al: Treatment of phenprocoumon intoxication with cholestyramine. Br Med J 1977; 2:439. PubMed
Keep reading about Cholestyramine Resin
Keep reading about Dicumarol
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