Psyllium and Glimepiride: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Psyllium
Glimepiride
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
Increased risk of hypoglycemia
Interaction Deep Dive
In healthy volunteers, the mean area-under-the-curve (AUC) for glucose and insulin were reduced when psyllium was administered with a glucose load1. Closely monitor blood glucose levels and signs and symptoms of hypoglycemia when psyllium and antidiabetic agents are used together.
Why it happens (mechanism)
Additive blood glucose-lowering effects
Literature reports
1 report — tap to read
a) In 10 healthy female volunteers, psyllium significantly reduced postprandial glucose concentration, and insulin secretion in a randomized, cross-over study. Psyllium 10.5 grams was administered mixed with a 50 gram glucose load in aqueous solution. The mean area-under-the-curve (AUC) (zero to 4 hours) for glucose decreased by 11.1 percent (p less than 0.05), and the mean AUC (zero to 4 hours) for insulin decreased by 36.1 percent (p less than 0.05). Large individual differences were observed 1.
Common questions
Can I take Psyllium and Glimepiride together?
Increased risk of hypoglycemia Always confirm with your pharmacist or prescriber before making any change.
How serious is the Psyllium and Glimepiride 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 Psyllium or Glimepiride 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)
- Sierra M, Garcia JJ, Fernandez N, et al: Effects of ispaghula husk and guar gum on postprandial glucose and insulin concentrations in healthy subjects. Eur J Clin Nutr 2001; 55(4):235-243. DOI
Keep reading about Glimepiride
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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