A 62-year-old woman with type 2 diabetes is started on glipizide. Two weeks later she develops sweating, palpitations, and confusion 3 hours after a meal. Blood glucose is 48 mg/dL. Which property of sulfonylureas best explains this adverse effect?
- A They inhibit hepatic gluconeogenesis causing fasting hypoglycemia
- B They stimulate insulin secretion in a glucose-independent manner ✓
- C They increase peripheral insulin resistance through PPAR-gamma activation
- D They delay gastric emptying and cause postprandial hypoglycemia
Correct answer: B. They stimulate insulin secretion in a glucose-independent manner
Explanation
Sulfonylureas close K-ATP channels on beta cells, triggering insulin secretion regardless of ambient glucose, which causes hypoglycemia even when glucose is low. Metformin inhibits gluconeogenesis but rarely causes hypoglycemia. Pioglitazone activates PPAR-gamma. Delayed gastric emptying is a GLP-1 agonist effect.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
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