Glyburide lowers blood glucose primarily by which action?

• A. Stimulates pancreas to produce insulin
• B. Lowers glucose by increasing peripheral uptake
• C. Inhibits hepatic glucose production
• D. Delays intestinal glucose absorption

Answer: (A)

Glyburide lowers blood glucose primarily by stimulating insulin secretion from the pancreas. It’s a sulfonylurea that binds to receptors on pancreatic beta cells and closes ATP-sensitive potassium channels. This causes the cell to depolarize, opens voltage-gated calcium channels, and increases intracellular calcium, triggering exocytosis of insulin-containing granules. The resulting rise in insulin promotes glucose uptake into muscles and fat and helps suppress glucose production by the liver, leading to lower blood glucose.

This relies on some remaining beta-cell function, so it’s less effective if beta cells are severely damaged. Because it increases insulin release, there’s a risk of hypoglycemia. It doesn’t act by directly increasing peripheral uptake without insulin, delaying intestinal glucose absorption, or inhibiting hepatic glucose production—those effects belong to other drug classes.