Nationwide, there have been dozens of cases of infant deaths associated with overdoses of cocaine, meth and other illegal substances via breast milk. Adverse effects are also possible in cases where prescribed doses of legal drugs, such as painkillers, are taken by the mother while breastfeeding.
"Some people think that using drugs and nursing won't affect the child, but that's not true at all," said Bruce Goldberger, director of toxicology at the University of Florida College of Medicine in Gainesville. "There have been hundreds of studies with pharmaceutical drugs that show that these substances are delivered to the child through breast milk.
"Children are very fragile beings," he added. "It doesn't take very much drug to alter their physiology and have a bad effect."
"Many antidepressants or psychotropic drugs will be distributed to breast milk and expose the nursing infant," said Luann White, director of the Tulane Center for Applied Environmental Health. "An infant is very tiny and cannot metabolize the drug as quickly as an adult, so a lethal dose would be much smaller for the infant than for the mother."
For that reason, mothers should always be careful about taking any drug, whether recreational or prescription, while nursing, toxicologists say.
Nursing mothers, Casavant said, should review all their medicines, even over-the-counter medicines, with their physicians, the child's pediatrician or their pharmacists.