Sulfisoxazole and Glimepiride: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Glimepiride
Sulfisoxazole
No brand names on record
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
Sulfonamides may displace highly protein-bound antidiabetic drugs12. Sulfonamides that inhibit CYP2C9 (e.g., sulfamethoxazole) 13 may increase exposure to CYP2C9 substrates, such as glimepiride, glyBURIDE, and nateglinide 315. Hypoglycemia has occurred during concomitant use of sulfonylureas and sulfonamides 117 and may occur with other antidiabetic drugs, including insulin. More frequent monitoring of glucose and dose adjustment may be required 2. Monitor for hypoglycemia, or worsening glycemic control, during concomitant use and when the sulfonamide is withdrawn 1.
Why it happens (mechanism)
Displacement of antidiabetic agent from protein-binding sites; inhibition of CYP2C9-mediated metabolism of some antidiabetic agents
Literature reports
2 reports — tap to read
a) A brief review of some of the case reports relating to these interactions follows: (1) A 69-year-old black female who was stable on cimetidine 300 mg orally at bedtime, docusate 200 mg daily, hydrochlorothiazide 50 mg daily, and chlorproPAMIDE 500 mg daily orally, was hospitalized two days after starting cotrimoxazole two tablets orally twice a day. Her laboratory results on admission were a blood glucose of 48 mg/dL, blood pressure of 174/90, and serum sodium of 118 mEq/L; she was nauseous and vomiting. The patient was discharged after seven days of hospitalization 7. (2) A 67-year-old patient with diabetes stable on chlorproPAMIDE 250 mg daily was admitted to a hospital two days after starting on sulfamethazine with a blood glucose of 10 mg/dL. She was semicomatose for a week and mentally dull for a month 8. (3) A 77-year-old man on chlorproPAMIDE and phenformin was started on sulfisoxazole. The next day he was hospitalized with hypoglycemia 910. (4) describe two patients on tolbutamide who were started on sulfisoxazole. They experienced hypoglycemia and were hospitalized. One of the patients, a 47-year-old man, died with a blood glucose of 8 mg/dL.
b) Symptomatic hypoglycemia developed in an 83-year-old man three days after cotrimoxazole was added to glipiZIDE therapy . This patient may have been at increased risk for this drug interaction because of increased age and a history of alcohol abuse. This type of interaction has also been reported with glyburide and cotrimoxazole, as well as chlorpropamide and cotrimoxazole. Monitor the patient for hypoglycemia if cotrimoxazole is added to oral hypoglycemic therapy 11.
Common questions
Can I take Sulfisoxazole and Glimepiride together?
Increased risk of hypoglycemia Always confirm with your pharmacist or prescriber before making any change.
How serious is the Sulfisoxazole and Glimepiride interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Sulfisoxazole 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 (13)
- Product Information: AMARYL(R) oral tablets, glimepiride oral tablets. Sanofi-Aventis U.S. LLC (per FDA), Bridgewater, NJ, 2013. DailyMed
- Product Information: TOUJEO(R) subcutaneous injection, insulin glargine subcutaneous injection. sanofi-aventis (per manufacturer), Bridgewater, NJ, 2015. DailyMed
- Product Information: Glynase(R) PresTab(R) oral micronized tablets, glyburide oral micronized tablets. Pharmacia & Upjohn Co (per FDA), New York, NY, 2013. DailyMed
- Product Information: SYMLIN(R) subcutaneous injection, pramlintide acetate subcutaneous injection. AstraZeneca Pharmaceuticals LP (per FDA), Wilmington, DE, 2015. DailyMed
- Product Information: Starlix(R) oral tablets, nateglinide oral tablets. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2011. DailyMed
- Product Information: AFREZZA(R) oral inhalation powder, insulin human oral inhalation powder. MannKind Corporation(TM) (per manufacturer), Danbury, CT, 2014. DailyMed
- Baciewicz A & Swafford W: Hypoglycemia induced by the interaction of chlorpropamide and co-trimoxazole. Drug Intell Clin Pharm 1984; 18:309-310. PubMed
- Dall JL, Conway H, & McAlpine SG: Hypoglycaemia due to chlorpropamide. Scott Med J 1967; 12:403-404. DOI
- Tucker HS Jr & Hirsch JI: Sulfonamide-sulfonylurea interaction (letter). N Engl J Med 1972; 286:110-111. PubMed
- Soeldner JS & Streinke J: Hypoglycemia in tolbutamide-treated diabetes. JAMA 1965; 193:398-399. DOI
- Johnson JF & Dobmeier ME: Symptomatic hypoglycemia secondary to a glipizide-trimethoprim/sulfamethoxazole drug interaction. DICP 1990; 24:250-251. PubMed
- Christensen L, Hansen J, & Kristensen M: Sulphaphenazole-induced hypoglycaemic attacks in tolbutamide-treated diabetics. Lancet 1963; 2:1298-1301.
- Product Information: sulfamethoxazole trimethoprim oral suspension, sulfamethoxazole trimethoprim oral suspension. Aurobindo Pharma USA, Inc. (per DailyMed), Dayton, NJ, 2013.
Keep reading about Glimepiride
Keep reading about Sulfisoxazole
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