PSYCHOTROPIC MEDICATIONS IN LACTATION

The use of psychotropic medications during lactation has not been inve stigated in a controlled and systematic fashion. The literature is lad en with case reports and small case series containing numerous confoun ds that render the establishment of definitive treatment guidelines te nuous. The increasing number of women who plan to breast-feed and the high rate of psychiatric illness during the postpartum period undersco re the need to develop such guidelines. A MEDLINE search was conducted for key words either in the titles or abstracts of publications citin g the use of psychotropic medications in lactating women and describin g the pharmacokinetics of medication excretion into boast milk. The pu blications identified span over three decades. The largest single stud y by one group of investigators examined 12 mother-infant pairs. The m ajority of studies report their results as a ratio of the breast milk concentration to the maternal serum concentration (milk/plasma [M/P]) ratio. Estimations that use the M/P ratio of the infant daily dose ran ge from 0.1% to 6.2% of the maternal dose. Few studies attempt to acco unt for the complex variations in the maternal, breast milk, and infan t physiologic environments. The major confounds of the studies reviewe d include (I) failure to document portion of breast milk assayed (fore milk versus hindmilk), (2) limited metabolite assay, (3) limited assay sensitivity (1-25 ng/mL), not of research quality, (4) concomitant ma ternal and/or infant medications, and (5) medication exposure during p regnancy. Despite these confounds, there are remarkably few reports of adverse effects on nursing infants exposed to psychotropic medication s in breast milk. The limited data confirm that psychotropic medicatio ns are excreted into breast milk and that the infant is exposed to the se medications. The ideal breast milk study that accounts for the conf ounds identified has not been completed. The complex matrix of breast milk and the changing infant metabolic capacity will require a more de tailed analysis with assays of improved sensitivity. Despite the limit ed reports of adverse effects on nursing infants, the limitations of t he available literature and minimal sample sizes make it premature to recommend specific medications from a given class. There is inadequate data on nursing infant exposure to multiple medications to support ch anging medication to a different agent in an otherwise stable patient. An individualized risk/benefit assessment with the empirical goal of minimizing infant exposure while maintaining maternal emotional health is the ideal approach.