Cholestyramine and Doxercalciferol: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cholestyramine
Doxercalciferol
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
Reduced doxercalciferol efficacy
Interaction Deep Dive
Cholestyramine has been reported to reduce intestinal absorption of fat-soluble vitamins. Therefore, it may impair intestinal absorption of doxercalciferol capsules. Administer doxercalciferol capsules at least 1 hour before or 4 to 6 hours after taking cholestyramine1.
Why it happens (mechanism)
Reduced intestinal absorption of doxercalciferol
Common questions
Can I take Cholestyramine and Doxercalciferol together?
Reduced doxercalciferol efficacy Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cholestyramine and Doxercalciferol interaction?
It is rated minor. Usually limited clinical impact.
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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Cholestyramine or Doxercalciferol 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 (1)
- Product Information: HECTOROL(R) oral capsules, intravenous injection, doxercalciferol oral capsules, intravenous injection. Genzyme Corporation (per FDA), Cambridge, MA, 2018.
Keep reading about Cholestyramine
Keep reading about Doxercalciferol
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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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