<s>[INST] context: Glyburide Glyburide is a second-generation sulfonylurea oral hypoglycemic. Of the main groups or chemical classes of oral antidiabetic agents, these are the ones typically associated with causing hypoglycemia, whether from overdose or as a rather expected response in some patients, paicularly before meals. Normally carbohydrates from a meal trigger insulin release; when blood glucose levels are low, as after the 18-h fast this patient experienced, physiologic insulin release would be low too. However, even in a fast-induced hypoglycemic state a sulfonylurea will release insulin and drive blood glucose down even fuher. The elderly are paicularly susceptible to sulfonylurea-induced hypoglycemia. Pa of this may relate to diet. However, expected age-related falls of renal and/or hepatic function can reduce elimination of these drugs, thereby increasing their serum levels and their effects unless dosages are reduced accordingly. This propensity for preprandial hypoglycemia is shared by the meglitinides, repaglinide and nateglinide because they, too, increase pancreatic insulin release. The thiazadolinediones (glitazones) seldom cause symptomatic hypoglycemia because they do not release insulin. The same applies to metformin, the biguanide; and acarbose (with, along with miglitol, is an aglucosidase inhibitor). Because of a longer half-life, compared with glipizide, a sulfonylurea is more likely to cause preprandial hypoglycemia. Glipizide is contraindicated in patients with liver disease because it is metabolized in the liver. Care should be taken in the elderly because of their propensity to develop hypoglycemia, which is perhaps due to decreased hepatic and renal function that is evident in this patient population. Metformin, acarbose, and pioglitazone do not produce serious hypoglycemic reactions. [/INST] question: A 75-yrs-old woman with diabetes is taking an oral antidiabetic drugs. One day she goes without eating for 18 h. Her serum glucose concentration is 48 mg/dL (hypoglycemic) upon arrival at the emergency depament, where she is deemed to be in critical condition. Which of the following drugs most likely aggravated this fasting hypoglycemia? | options: A: Acarbose B: Glyburide C: Metformin D: Pioglitazone | answer: B </s>