Fentanyl is listed among the drugs compatible with breastfeeding.
The available studies are referred to children of patients undergoing general anesthesia during labor and not regular users of the drug, so that the data have more connection with the transplacental passage of the substance that transport through breast milk. In those cases seems not to have limitations to the establishment of breastfeeding, but in a certain proportion of children whose mothers were subjected to the drug during childbirth was evidenced lower neurologic assessment score than in the children of mothers who were not exposed to the drug, but without any clinical significance or differences in subsequent evolution.
Regarding postpartum administration of intravenous doses or transdermal fentanyl, there is no published experience, so it is recommended to use best-studied drugs. Some experts recommend not stop breastfeeding if necessary fentanyl after birth, but should be closely monitored infant development, especially neuromotor maturation, weight curve and alertness.
If possible, the dose of fentanyl should be decreased and complementing with non-narcotic analgesic therapy.
Warning of the manufacturer:
Fentanyl passes into breast milk and can cause extreme drowsiness and shallow breathing in the baby. Consult your doctor and do not take fentanyl while breastfeeding unless your doctor believes that the benefits to you outweigh the risks to the child.