Sulfonylureas stimulate endogenous insulin secretion. They can cause hypoglycemia. Its pharmacokinetic data (moderately high molecular weight and very high percentage of plasma protein binding) explain the zero or negligible passage into breast milk observed (Serrano 2014, Glatstein 2009, Feig 2007and 2005). Although blood sugar levels were normal in an infant whose mother was taking glibencamide (Feig 2005), one author suggests monitoring for symptoms of hypoglycemia in the infant (Glatstein 2009). List of WHO essential medicines: compatible with breastfeeding (WHO / UNICEF 2002). Diet, exercise, and breastfeeding improve blood sugar levels.