Which of the following is a second generation sulfonylurea?

• A. Glibenclamide (glyburide)
• B. Chlorpropamide
• C. Tolbutamide
• D. Metformin

Answer: (A)

Second-generation sulfonylureas are the newer, more potent members of this drug class, designed to stimulate insulin release at much lower doses. Glibenclamide (glyburide) is part of this group, which is why it is identified as a second-generation sulfonylurea. In contrast, chlorpropamide and tolbutamide are older first-generation agents, and metformin is not a sulfonylurea at all—it belongs to the biguanide class and works through a different mechanism. So glibenclamide stands out as the second-generation sulfonylurea.