Sulfonylureas

Sulfonylureas (glipizide, glyburide, glimepiride) lower blood glucose by stimulating pancreatic beta cells to release insulin, regardless of the current glucose level. This insulin-dependent mechanism is why they carry a real hypoglycemia risk — the pancreas releases insulin even when glucose is already dropping. They are used in type 2 diabetes when lifestyle changes and first-line agents are insufficient, but they require functioning beta cells, so they are ineffective in type 1 diabetes. Hypoglycemia is the most dangerous adverse effect; it is more common with glyburide (longer half-life, active metabolites) and in older adults, malnourished clients, or those who skip meals. Weight gain is expected because circulating insulin promotes fat storage. Teach the client to eat regular meals, recognize hypoglycemia symptoms (tremors, diaphoresis, tachycardia, confusion), and carry a fast-acting glucose source at all times. Monitor fasting glucose, HbA1c, and renal function. Glyburide is generally avoided in renal impairment and older adults; glipizide is preferred because its metabolites are inactive. Alcohol potentiates hypoglycemia and can trigger a disulfiram-like reaction, especially with chlorpropamide (a first-generation agent rarely used today).