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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Sulfonylurea [EPC]
Glyburide is a second-generation sulfonylurea used to improve glycemic control in adults with type 2 diabetes mellitus. It works by stimulating insulin release from the pancreas and is often prescribed alongside diet and exercise.
Name
Glyburide
Raw Name
GLYBURIDE
Category
Sulfonylurea [EPC]
Drug Count
3
Variant Count
88
Last Verified
February 17, 2026
RxCUI
861748, 861753, 310534, 310537, 861743, 197737
UNII
786Z46389E, SX6K58TVWC
About Glyburide
Glyburide is a second-generation sulfonylurea used to improve glycemic control in adults with type 2 diabetes mellitus. It works by stimulating insulin release from the pancreas and is often prescribed alongside diet and exercise.
Detailed information about Glyburide
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Glyburide.
In the context of the complex pathophysiology of type 2 diabetes, Glyburide serves as an insulin secretagogue (a substance that causes another substance to be secreted). It is indicated as an adjunct to diet and exercise to improve glycemic control in adults. It is important to note that Glyburide is ineffective in patients with type 1 diabetes mellitus, where the pancreas is incapable of producing insulin, or in the treatment of diabetic ketoacidosis (a life-threatening complication of diabetes), as these conditions require exogenous insulin therapy. Over the years, while newer classes of drugs like SGLT2 inhibitors and GLP-1 receptor agonists have emerged, Glyburide continues to be utilized due to its robust efficacy in lowering Hemoglobin A1c (HbA1c) levels, often by 1% to 2% when used as monotherapy.
To understand how Glyburide works, one must look at the cellular level of the pancreatic beta cells. Glyburide functions by binding to specific receptors on the surface of these cells, known as sulfonylurea receptors (SUR1). These receptors are closely associated with ATP-sensitive potassium (K-ATP) channels. Under normal physiological conditions, an increase in blood glucose leads to increased ATP production within the beta cell, which closes these potassium channels, depolarizes the cell membrane, and triggers the influx of calcium, ultimately leading to insulin secretion.
Glyburide bypasses the need for high glucose levels by directly binding to the SUR1 subunit and forcing the K-ATP channels to close. This induces a state of membrane depolarization regardless of the ambient glucose concentration. This depolarization opens voltage-gated calcium channels, allowing calcium ions to flow into the cell. The rise in intracellular calcium triggers the exocytosis (release) of insulin granules into the bloodstream. Because Glyburide stimulates insulin release even when blood sugar levels might not be excessively high, it carries a significant risk of hypoglycemia (low blood sugar) compared to some other diabetes medications. Additionally, long-term use of Glyburide may enhance peripheral insulin sensitivity and decrease hepatic (liver) glucose production, although its primary clinical effect remains the stimulation of the pancreas.
Understanding the pharmacokinetics of Glyburide is essential for safe prescribing and patient management, as its duration of action and metabolic pathways influence the risk of adverse events.
Glyburide is FDA-approved for the following indications:
Glyburide is available in several oral tablet strengths and formulations:
> Important: Only your healthcare provider can determine if Glyburide is right for your specific condition. The choice of formulation and dose must be individualized based on your blood glucose levels, renal function, and risk of hypoglycemia.
Dosage of Glyburide must be individualized based on the patient's glycemic response and tolerance. There is no fixed dosage regimen for the management of diabetes with Glyburide.
Glyburide is not currently FDA-approved for use in pediatric patients. Safety and effectiveness in children have not been established. In cases of neonatal diabetes (a rare genetic form), other sulfonylureas or specific genetic-based therapies are typically managed by pediatric endocrinologists.
Glyburide is not recommended for patients with severe renal impairment (CrCl < 30 mL/min) or those on dialysis. Because Glyburide has active metabolites that are cleared by the kidneys, renal dysfunction leads to drug accumulation and a very high risk of prolonged, severe hypoglycemia. In mild to moderate renal impairment, healthcare providers usually start at the lowest possible dose (1.25 mg) and monitor blood glucose levels closely.
In patients with impaired liver function, the metabolism of Glyburide may be slowed, and the liver's ability to produce glucose (gluconeogenesis) may be compromised. Both factors increase the risk of severe hypoglycemia. Healthcare providers typically use very conservative dosing and frequent monitoring in these patients.
Elderly patients are particularly susceptible to the hypoglycemic effects of sulfonylureas. The American Geriatrics Society's Beers Criteria recommends avoiding Glyburide in the elderly due to its long half-life and the risk of prolonged hypoglycemia. If used, the starting dose should be 1.25 mg (conventional) or 0.75 mg (micronized), and titration should be extremely slow.
If you miss a dose of Glyburide, take it as soon as you remember, provided you are about to eat a meal. If it is almost time for your next meal, skip the missed dose and return to your regular schedule. Never take two doses at once to make up for a missed one, as this can cause dangerously low blood sugar levels.
An overdose of Glyburide can cause severe, life-threatening hypoglycemia.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, as this can lead to hyperglycemia (high blood sugar) and related complications.
> Warning: Stop taking Glyburide and call your doctor immediately if you experience any of these.
No FDA black box warnings currently exist for Glyburide. However, the FDA does require a special warning section regarding "Special Warning on Increased Risk of Cardiovascular Mortality." This warning is based on the University Group Diabetes Program (UGDP) study, which suggested that oral hypoglycemic drugs might be associated with higher cardiovascular death rates compared to diet alone or diet plus insulin. This remains a topic of clinical discussion, and patients should discuss their individual cardiovascular risk profile with their physician.
Report any unusual symptoms to your healthcare provider immediately to ensure your treatment plan remains safe and effective.
Glyburide is a potent medication that requires careful monitoring. The most critical safety point is the prevention and management of hypoglycemia. Patients must be educated on the symptoms of low blood sugar and must always carry a source of fast-acting carbohydrate (like glucose tablets). Furthermore, Glyburide should not be used in patients with type 1 diabetes or for the treatment of diabetic ketoacidosis.
There are no official FDA Black Box Warnings for Glyburide. However, as noted in the side effects section, there is a significant "Special Warning" regarding cardiovascular mortality that applies to the entire class of sulfonylureas. This warning suggests that patients taking oral blood-sugar-lowering drugs may have a higher risk of heart-related death than those treated with diet alone or insulin, although newer clinical data have provided more nuanced views on this risk.
To ensure the safe use of Glyburide, the following lab tests and monitoring are typically required:
Glyburide can cause hypoglycemia, which may impair your ability to concentrate or react. Do not drive or operate heavy machinery until you know how Glyburide affects your blood sugar and you are confident your levels are stable. Always keep a source of sugar in your vehicle.
Alcohol consumption should be strictly limited. Alcohol can potentiate the hypoglycemic effect of Glyburide, making a dangerous drop in blood sugar more likely. Furthermore, some patients experience a "disulfiram-like" reaction (flushing, nausea, rapid heartbeat) when drinking alcohol while on this medication.
Do not stop taking Glyburide abruptly unless directed by your doctor. Stopping the medication can cause a rapid rise in blood sugar (rebound hyperglycemia). If you need to stop the drug, your healthcare provider will likely transition you to another medication or insulin to maintain glycemic control.
> Important: Discuss all your medical conditions, especially heart, kidney, or liver disease, with your healthcare provider before starting Glyburide.
Glyburide does not typically interfere with common laboratory tests, but it is important to inform laboratory personnel that you are taking a sulfonylurea, as severe hypoglycemia can affect the interpretation of certain metabolic panels.
For each major interaction, the mechanism usually involves either pharmacokinetic changes (altering how the drug is absorbed, metabolized, or excreted) or pharmacodynamic changes (drugs having similar or opposing effects on blood sugar). Management typically involves more frequent blood glucose monitoring and dose adjustments.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter pain relievers and cold medicines.
Glyburide must NEVER be used in the following circumstances:
Conditions requiring careful risk-benefit analysis include:
Patients with a known allergy to other sulfonylureas (like glipizide or glimepiride) or sulfonamides (sulfa antibiotics) may demonstrate cross-sensitivity to Glyburide. While many patients with sulfa-antibiotic allergies can tolerate sulfonylureas, the first dose should be administered with caution and under medical supervision if the previous reaction was severe.
> Important: Your healthcare provider will evaluate your complete medical history, including kidney function and allergy history, before prescribing Glyburide.
FDA Pregnancy Category B (Conventional) / C (Micronized).
While animal studies have not shown clear evidence of fetal harm, Glyburide does cross the placenta. Most clinical guidelines, including those from the American Diabetes Association (ADA), recommend insulin as the first-line treatment for diabetes during pregnancy because it does not cross the placenta and provides more precise control. If Glyburide is used, it should be discontinued at least two weeks before the expected delivery date to avoid prolonged, severe hypoglycemia in the newborn.
It is not known with certainty whether Glyburide is excreted in human milk. However, some sulfonylureas are known to be excreted. Because of the potential for hypoglycemia in the nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. If the mother continues taking Glyburide while breastfeeding, the infant should be closely monitored for signs of hypoglycemia (e.g., jitteriness, poor feeding, lethargy).
Safety and effectiveness in pediatric patients have not been established. Glyburide is not recommended for use in children with type 2 diabetes; metformin and insulin are the primary approved pharmacological treatments for this population.
Geriatric patients (age 65 and older) are at significantly higher risk for Glyburide-induced hypoglycemia. This is due to age-related declines in renal function and a higher prevalence of polypharmacy (taking multiple medications). The Beers Criteria specifically lists Glyburide as a medication to avoid in the elderly. If it must be used, healthcare providers start with the lowest possible dose and monitor the patient very closely for cognitive changes or falls, which are often the first signs of hypoglycemia in this age group.
In patients with kidney disease, the clearance of Glyburide and its active metabolites is reduced. This leads to a longer duration of action and a higher risk of "stacking" doses.
Liver disease can reduce the metabolism of Glyburide and also impair the liver's ability to respond to low blood sugar. Use in patients with significant hepatic impairment is generally discouraged. If used, very low doses and frequent monitoring are mandatory.
> Important: Special populations require individualized medical assessment and often more frequent blood glucose monitoring than the general population.
Glyburide is a second-generation sulfonylurea that acts primarily by stimulating insulin secretion from the pancreatic beta cells. At the molecular level, Glyburide binds with high affinity to the Sulfonylurea Receptor 1 (SUR1), which is a regulatory subunit of the ATP-sensitive potassium (K-ATP) channel located on the plasma membrane of beta cells.
Under normal conditions, these channels are open, allowing potassium to exit the cell and maintaining a polarized (negative) resting membrane potential. When Glyburide binds to SUR1, it causes the K-ATP channel to close. This prevents potassium efflux, leading to membrane depolarization. Depolarization triggers the opening of voltage-gated L-type calcium channels, allowing an influx of extracellular calcium. The resulting increase in intracellular calcium concentrations activates the microtubular system, causing the exocytosis of insulin-containing granules. This process is independent of the glucose concentration, which explains why Glyburide can cause hypoglycemia even during fasting states.
The primary pharmacodynamic effect is the lowering of blood glucose. The onset of the hypoglycemic effect typically occurs within 45 to 60 minutes, with the peak effect occurring at 2 to 4 hours. Although the plasma half-life is relatively short, the pharmacodynamic effect persists for up to 24 hours, likely due to the high affinity for the SUR1 receptor and the presence of weakly active metabolites. Chronic administration may also lead to extrapancreatic effects, such as increased sensitivity of peripheral tissues to insulin, though the clinical significance of these effects is secondary to the secretagogue action.
| Parameter | Value |
|---|---|
| Bioavailability | High (>90% for micronized; ~70-90% for conventional) |
| Protein Binding | >99% (primarily to Albumin) |
| Half-life | ~10 hours (biological effect lasts 24 hours) |
| Tmax | 2 to 4 hours (Conventional); 2 to 3 hours (Micronized) |
| Metabolism | Hepatic (CYP2C9) to two weakly active metabolites |
| Excretion | Renal 50%, Fecal 50% |
Glyburide belongs to the Sulfonylurea [EPC] class, specifically the second-generation subgroup. Related medications include Glipizide and Glimepiride. Second-generation sulfonylureas are generally more potent and have a more favorable side-effect profile than first-generation agents like Tolbutamide or Chlorpropamide.
Medications containing this ingredient
Common questions about Glyburide
Glyburide is an oral medication used to treat type 2 diabetes mellitus in adults. It belongs to a class of drugs called sulfonylureas, which work by stimulating the pancreas to release more insulin into the bloodstream. This helps lower blood sugar levels in patients whose diabetes is not sufficiently controlled by diet and exercise alone. It is not used for type 1 diabetes because the pancreas in those patients cannot produce insulin. Healthcare providers often prescribe it as a cost-effective option for long-term blood sugar management.
The most common side effect of Glyburide is hypoglycemia, or low blood sugar, which can cause shakiness, sweating, and confusion. Many patients also experience modest weight gain, usually between 2 and 7 pounds, because insulin helps the body store energy. Gastrointestinal issues like nausea, heartburn, or a feeling of fullness are also frequently reported when starting the medication. Some patients may notice mild skin itching or redness. Most of these side effects can be managed by taking the medication with food and following a consistent meal plan.
Drinking alcohol while taking Glyburide is generally discouraged and should be discussed with your doctor. Alcohol can interfere with the liver's ability to release glucose, which significantly increases the risk of severe and unpredictable hypoglycemia. Additionally, some people experience a 'disulfiram-like' reaction when mixing Glyburide and alcohol, which includes symptoms like intense flushing, nausea, vomiting, and a rapid heartbeat. If you do choose to drink, it should be done in moderation and always accompanied by food. Never drink alcohol on an empty stomach while using this medication.
Glyburide is generally not the first choice for managing diabetes during pregnancy. While it is classified as Pregnancy Category B or C depending on the formulation, insulin is the preferred treatment because it does not cross the placenta. Glyburide does cross the placenta and has been associated with a risk of neonatal hypoglycemia (low blood sugar in the newborn) if taken near the time of delivery. Some doctors may use it off-label if insulin is not an option, but this requires close specialist supervision. Always consult your obstetrician or endocrinologist if you are pregnant or planning to become pregnant while taking Glyburide.
Glyburide begins to lower blood sugar levels fairly quickly, usually within 45 to 60 minutes after taking a dose. The peak effect on your blood sugar typically occurs about 2 to 4 hours after administration. However, it may take several days of consistent use for your healthcare provider to see the full impact on your fasting blood glucose levels. Significant improvements in your Hemoglobin A1c (HbA1c) levels are usually seen after 3 months of therapy. Because it works quickly, it is vital to eat a meal immediately after taking the medication.
You should not stop taking Glyburide suddenly without consulting your healthcare provider. Stopping the medication abruptly can cause your blood sugar levels to rise rapidly, a condition known as hyperglycemia. This can lead to symptoms like increased thirst, frequent urination, and blurred vision, and over time, it increases the risk of serious diabetes complications. If you need to stop Glyburide due to side effects or a change in treatment, your doctor will provide a plan to taper the dose or switch you to another medication. Always maintain your diet and exercise routine even if your medication changes.
If you miss a dose of Glyburide, you should take it as soon as you remember, but only if you are about to eat a meal. If you do not plan on eating soon, or if it is almost time for your next scheduled dose, skip the missed dose entirely. Never take two doses at the same time to make up for a missed one, as this creates a very high risk of dangerous hypoglycemia. Consistency is key with Glyburide, so try to take it with breakfast every day. If you find yourself frequently forgetting doses, talk to your doctor about strategies to help you remember.
Yes, weight gain is a well-documented side effect of Glyburide and other sulfonylurea medications. This happens because the medication increases insulin levels, and insulin is a hormone that promotes the storage of fat and prevents the breakdown of fat cells. Additionally, some patients may eat extra calories to treat or prevent the symptoms of low blood sugar. Most clinical studies show an average weight gain of about 1 to 3 kilograms (2 to 6 pounds) when starting the drug. Working with a dietitian and maintaining a regular exercise program can help minimize this effect.
Glyburide can be taken with many other medications, but it also has several significant drug interactions. It is frequently prescribed alongside Metformin to provide better blood sugar control than either drug alone. However, it can interact with common drugs like aspirin, certain antibiotics, and antifungal medications, which can either increase the risk of low blood sugar or make Glyburide less effective. Beta-blockers for heart disease can also mask the warning signs of low blood sugar. Always provide your doctor and pharmacist with a complete list of all prescriptions, over-the-counter drugs, and supplements you are taking.
Yes, Glyburide is widely available as a low-cost generic medication in both conventional and micronized formulations. Generic versions are bioequivalent to the original brand-name drugs like Diabeta, Micronase, and Glynase. Because it is available as a generic, it is often one of the most affordable options for patients managing type 2 diabetes. However, keep in mind that generic versions of the micronized form are not interchangeable with generic versions of the conventional form. Always check with your pharmacist to ensure you are receiving the specific formulation prescribed by your doctor.