Sulfinpyrazone and Nateglinide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Sulfinpyrazone
No brand names on recordNateglinide
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 nateglinide bioavailability
Interaction Deep Dive
The coadministration of sulfinpyrazone with nateglinide produced statistically significant, yet modest increases in nateglinide bioavailability. The effect of sulfinpyrazone upon steady-state nateglinide dosing was not addressed during the study1.
Why it happens (mechanism)
Inhibition of P450-2C9-mediated nateglinide metabolism
Literature reports
1 report — tap to read
a) The coadministration of sulfinpyrazone with nateglinide produced statistically significant, yet modest increases in nateglinide bioavailability. In an open-label, randomized, 2-phase crossover pharmacokinetic study, healthy subjects (n=16) received a single oral dose of nateglinide 120 milligrams (mg) alone on study day 1, or after an overnight fast on the final day of a 7-day regimen of sulfinpyrazone 200 mg twice daily. Nateglinide plasma concentrations were measured by serial blood analysis performed over the 24-hour post-dose time period. The maximum serum concentration of nateglinide (Cmax) and time to maximum concentration (Tmax) were unaffected by concomitant administration of sulfinpyrazone; however, a modest yet statistically significant increase (28%) was observed in nateglinide area under the concentration-time curve (AUC - 0 to infinity). The geometric mean ratio for the AUC (0-infinity) was 1.28 (90% confidence interval, 1.19 to 1.37; p less than 0.01). While there were no occurrences of hypoglycemia observed throughout the study, the effect of sulfinpyrazone upon steady-state nateglinide dosing was not addressed 1.
Common questions
Can I take Sulfinpyrazone and Nateglinide together?
Increased nateglinide bioavailability Always confirm with your pharmacist or prescriber before making any change.
How serious is the Sulfinpyrazone and Nateglinide interaction?
It is rated minor. Usually limited clinical impact.
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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Sulfinpyrazone or Nateglinide 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)
- Sabia H, Sunkara G, Ligueros-Saylan M, et al: Effect of a selective CYP2C9 inhibitor on the pharmacokinetics of nateglinide in healthy subjects. Eur J Clin Pharmacol 2004; 60:407-412. PubMed
Keep reading about Sulfinpyrazone
Keep reading about Nateglinide
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist