Harmful Chemicals and Drugs in Breast Milk

The pediatrician should be aware of the fact that nearly all drugs used in the therapy of lactating women may be found in varying amounts in breast milk. Mothers who must take antithyroid drugs, chloramphenicol, lithium, methadone, most anticancer drugs, radioactive pharmaceuticals and antiinfective agents such as the tetracyclines and metronidazole should not nurse their infants while receiving therapy. It has been our experience that in most instances safer alternative drugs may be selected after discussions with obstetricians, family physicians, and internists. The use of other drugs merits a certain degree of caution; nursing the infant before a dose is given may help to minimize exposure to the infant. Interruption of breast-feeding should be infrequent.