Psychotropic Medications in Lactation

The use of psychotropic medications during lactation has not been investigated in a controlledand systematic fashion. The literature is laden with case reports and small case seriescontaining numerous confounds that render the establishment of definitive treatment guidelinestenuous. The increasing number of women who plan to breast-feed and the high rate ofpsychiatric illness during the postpartum period underscore the need to develop such guidelines.A MEDLINE search was conducted for key words either in the titles or abstracts of publicationsciting the use of psychotropic medications in lactating women and describing thepharmacokinetics of medication excretion into breast milk. The publications identified spanover three decades. The largest single study by one group of investigators examined 12 motherinfantpairs. The majority of studies report their results as a ratio of the breast milk concentrationto the maternal serum concentration (milk/plasma [M/P]) ratio. Estimations that use theM/P ratio of the infant daily dose range from 0.1% to 6.2% of the maternal dose. Few studiesattempt to account for the complex variations in the maternal, breast milk, and infant physiologicenvironments. The major confounds of the studies reviewed include (1) failure to documentportion of breast milk assayed (foremilk versus hindmilk), (2) limited metabolite assay,(3) limited assay sensitivity (1-25 ng/mL), not of research quality, (4) concomitant maternaland/or infant medications, and (5) medication exposure during pregnancy. Despite these confounds,there are remarkably few reports of adverse effects on nursing infants exposed to psychotropicmedications in breast milk. The limited data confirm that psychotropic medicationsare excreted into breast milk and that the infant is exposed to these medications. The idealbreast milk study that accounts for the confounds identified has not been completed. The complexmatrix of breast milk and the changing infant metabolic capacity will require a more detailedanalysis with assays of improved sensitivity. Despite the limited reports of adverse effectson nursing infants, the limitations of the available literature and minimal sample sizesmake it premature to recommend specific medications from a given class. There is inadequatedata on nursing infant exposure to multiple medications to support changing medication to adifferent agent in an otherwise stable patient. An individualized risk/benefit assessment withthe empirical goal of minimizing infant exposure while maintaining maternal emotional healthis the ideal approach.