Cholestyramine and Glipizide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cholestyramine
Glipizide
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 glipiZIDE effectiveness; increased blood glucose
Interaction Deep Dive
Concurrent use of cholestyramine and glipiZIDE may reduce the bioavailability of glipiZIDE, resulting in higher blood glucose in some patients1.
Why it happens (mechanism)
Decreased glipiZIDE absorption
Literature reports
1 report — tap to read
a) In six healthy subjects, the concurrent use of cholestyramine 8 grams decreased the bioavailability of glipiZIDE 5 mg. The peak glipiZIDE concentration was reduced by 33% and the bioavailability was reduced by about 30%. When this combination is required, monitor for a possible slight rise in glucose 1.
Common questions
Can I take Cholestyramine and Glipizide together?
Decreased glipiZIDE effectiveness; increased blood glucose Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cholestyramine and Glipizide 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 "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Cholestyramine or Glipizide 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)
- Kivisto KT & Neuvonen PJ: The effect of cholestyramine and activated charcoal on glipizide absorption. Br J Clin Pharmacol 1990; 30:733-736. PubMed
Keep reading about Cholestyramine
Keep reading about Glipizide
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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