What is the mechanism of metformin in type 2 diabetes management?

• A. Increases insulin secretion
• B. Decreases hepatic glucose production and increases insulin sensitivity
• C. Inhibits intestinal glucose absorption
• D. Decreases hepatic glucose production and increases insulin sensitivity

Answer: (D)

Metformin lowers blood glucose mainly by two actions: it reduces the liver’s production of glucose and it improves how tissues respond to insulin. In the liver, metformin activates AMPK, which suppresses gluconeogenesis, so hepatic glucose output decreases. In peripheral tissues, it enhances insulin sensitivity, especially in muscle, leading to better uptake and utilization of glucose. Because it doesn’t stimulate pancreatic insulin secretion, it rarely causes hypoglycemia when used alone. It’s not primarily about blocking intestinal glucose absorption, so that mechanism isn’t the main effect of metformin.