Tolbutamide is no longer marketed in the United States. It is excreted into breastmilk in small amounts that should cause no harm to the breastfed infant. Monitor breastfed infants for signs of hypoglycemia such as jitteriness, excessive sleepiness, poor feeding, seizures cyanosis, apnea, or hypothermia. If there is concern, monitoring of the breastfed infant's blood glucose is advisable during maternal therapy with hypoglycemic agents.[1,2]