From the Guidelines
Glyburide works to lower blood sugar levels by stimulating the pancreas to release more insulin, with its main pharmacological effect being the increase of insulin levels by stimulating insulin secretion from pancreatic β cells. As a sulfonylurea medication, glyburide binds to specific receptors on the beta cells of the pancreas, causing these cells to close potassium channels. This closure leads to cell membrane depolarization, allowing calcium to enter the cells, which triggers the release of insulin from storage granules 1. The increased insulin in the bloodstream helps move glucose from the blood into cells throughout the body, particularly in muscle and fat tissues, where it can be used for energy or stored. Some key points to consider when using glyburide include:
- Glyburide can reduce HbA1c level by 1.0% to 1.5% 1
- The medication is usually taken once or twice daily with meals to reduce the risk of hypoglycemia, which is the most common side effect
- Glyburide should not be used by people with type 1 diabetes or those with severe liver or kidney disease, as it may cause dangerous drops in blood sugar levels in these populations
- Sulfonylureas, if used improperly, can lead to hypoglycaemia, particularly in elderly patients and in those with liver and kidney dysfunctions, and may also cause weight gain 1. It's most effective in people with type 2 diabetes who still have functioning pancreatic beta cells, and prospective and randomized clinical studies have shown that the use of sulfonylureas was associated with a reduced risk of diabetic microvascular and macrovascular diseases 1.
From the FDA Drug Label
CLINICAL PHARMACOLOGY Glyburide appears to lower the blood glucose acutely by stimulating the release of insulin from the pancreas, an effect dependent upon functioning beta cells in the pancreatic islets.
Glyburide works to lower blood sugar levels by stimulating the release of insulin from the pancreas. This effect is dependent on functioning beta cells in the pancreatic islets.
- The exact mechanism of how glyburide lowers blood glucose during long-term administration has not been clearly established 2.
From the Research
Mechanism of Glyburide
Glyburide is a sulfonylurea that works to lower blood sugar levels by:
- Stimulating the release of insulin from pancreatic cells 3
- Reducing the clearance rate of insulin in the liver 3
- Reducing the secretion of glucagon 3
- Enhancing the sensitivity of peripheral tissues to insulin in type 2 diabetes mellitus 3
- Decreasing hepatic glucose production (HGP) 4
Effects on Blood Sugar Levels
Studies have shown that glyburide can:
- Decrease fasting blood glucose levels by decreasing HGP 4
- Improve fasting plasma glucose, HbA(1C), and post-prandial glucose control when combined with metformin 5
- Have a similar effect on blood glucose levels as other sulfonylureas, such as glibenclamide, in the fasting state 6
- Have a less pronounced effect on hyperglycemia and lower insulin and C-peptide levels compared to glibenclamide in the postprandial state 6
Key Findings
- A low dose of glyburide (20 micrograms/kg body weight) can decrease HGP by 16% without increasing insulin secretion 4
- Glyburide is associated with a higher risk of hypoglycemia compared to modified-release gliclazide 7
- Combination therapy with glyburide and metformin can improve glycemic control in type 2 diabetes mellitus 5