Maternal use of oral opioids during breastfeeding can cause infant drowsiness, which may progress to rare but severe central nervous system depression. Limited data indicate that butorphanol is excreted into breastmilk in small amounts. Butorphanol is poorly orally absorbed, so it is unlikely to adversely affect the breastfed infant. Monitor the infant for drowsiness, adequate weight gain, and developmental milestones, especially in younger, exclusively breastfed infants. If butorphanol is required by the mother of a newborn, it is not a reason to discontinue breastfeeding; however, once