Colesevelam and Glyburide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Glyburide
Colesevelam
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 glyBURIDE exposure and plasma concentrations
Interaction Deep Dive
Concurrent use of glyBURIDE and colesevelam may result in decreased bioavailability of glyBURIDE. In one study, concurrent administration of colesevelam with glyBURIDE significantly reduced the exposure of glyBURIDE; however, reductions were minimal when the glyBURIDE was given 4 hours prior to colesevelam. In patients requiring coadministration of these agents, glyBURIDE should be taken at least 4 hours prior to colesevelam. Alternatively, patients should be monitored for an adequate response to glyBURIDE therapy and the glyBURIDE dose should be adjusted appropriately1.
Why it happens (mechanism)
Reduced absorption of glyBURIDE by nonspecific binding with colesevelam
Literature reports
1 report — tap to read
a) Concurrent administration of colesevelam with glyBURIDE in participants significantly reduced levels of glyBURIDE in one study. Coadministration of glyBURIDE 3 mg and colesevelam 3.75 g resulted in a 32% and 47% mean reduction in glyBURIDE AUC and Cmax, respectively. Administration of glyBURIDE 1 hour prior to colesevelam decreased the AUC and Cmax by 20% and 15%, respectively. When glyBURIDE was given 4 hours prior to colesevelam, the mean changes in AUC and Cmax were -7% and 4%, respectively 1.
Common questions
Can I take Colesevelam and Glyburide together?
Decreased glyBURIDE exposure and plasma concentrations Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colesevelam and Glyburide interaction?
It is rated moderate. Can be significant — usually manageable with 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 Colesevelam or Glyburide 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: WELCHOL oral tablets, colesevelam hcl oral tablets. Daiichi Sankyo Inc, Parsippany, NJ, 2008. DailyMed
Keep reading about Glyburide
Keep reading about Colesevelam
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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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