Serum Concentrations of Antidepressants and Benzodiazepines in Nursing Infants: A Case Series

The relative risk of psychotropic medication use in women with puerperal psychiatric illness who are breastfeeding has yet to be quantified adequately. Although the emotional and medical benefits of breastfeeding and adverse effects of maternal depression on infant development are well described, how these absolute benefits weigh against the potential effects of psychotropic drug use during lactation to ultimately guide clinical decisions is still unclear. The objective of this report was to evaluate the extent that psychotropic medications were present in the serum of infants breastfed by mothers treated with antidepressants and benzodiazepines. Serum samples were obtained from 35 nursing infants whose mothers were treated with psychotropic medications while breastfeeding. When a detectable concentration of medication was reported, information regarding infant behavior was obtained by maternal report. The Perinatal and Reproductive Psychiatry Program at Massachusetts General Hospital serves as a regional consultation center for the treatment of psychiatric disorders during pregnancy and the postpartum period. Subjects were mothers referred to the Perinatal Psychiatry Program for consultation regarding the relative safety of psychotropic medication use while breastfeeding. Presence of detectable levels of medication in infants whose mothers breastfed while taking psychotropic medications during pregnancy and/or during the puerperium and the well-being (based on maternal report) of infants who had detectable serum concentrations of medication. Seventy-four percent (n = 26) of infants had serum medication concentrations below the laboratory limit of detection (assay sensitivity 5-50 ng/mL). In the remaining 26% of the sample (n = 9), serum concentrations of psychotropic medications and/or active metabolites were detected. In each of these cases, infants had been exposed to the medication during pregnancy. Medications were not detected in infant serum when mothers had taken these agents solely during the postpartum period. No readily apparent difficulties with the infants were reported by mothers. These data support the low incidence of infant toxicity and adverse effects associated with antidepressant and benzodiazepine use during breastfeeding. These data also suggest that infant serum monitoring is helpful in the assessment of medication exposure in children of mothers who breastfeed while using psychotropic medications. Given the limited accumulated data