Tolbutamide and Clopidogrel: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Clopidogrel
Tolbutamide
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
An increased risk of hypoglycemia
Interaction Deep Dive
At high concentrations, in vitro studies have shown that clopidogrel inhibits the cytochrome P450 2C9 enzyme system. Because TOLBUTamide is at least partially metabolized by CYP 2C9, clopidogrel may interfere with its metabolism. Currently there are no data with which to predict the significance of this interaction. Caution should be utilized when these two agents are used concomitantly1.
Why it happens (mechanism)
Inhibition of cytochrome P450 2C9-mediated TOLBUTamide metabolism by clopidogrel
Common questions
Can I take Tolbutamide and Clopidogrel together?
An increased risk of hypoglycemia Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tolbutamide and Clopidogrel 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Tolbutamide or Clopidogrel 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: Plavix(R), clopidogrel. Bristol-Myers Squibb/Sanofi Pharmaceuticals Parternship, New York, NY, 2002. DailyMed
Keep reading about Clopidogrel
Keep reading about Tolbutamide
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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