Paroxetine in human breast milk and nursing infants

Objective: The purpose of this study was to determine the extent of infant medication exposure through breast-feeding during maternal treatment with p aroxetine. Method: Breast milk and paired maternal and infant sera were col lected after 10 days of maternal treatment with paroxetine at a stable dail y dose (10-50 mg/day). All samples were analyzed by means of high-performan ce liquid chromatography with ultraviolet detection and a limit of detectio n of 2 ng/ml. Results: Breast milk paroxetine concentrations were highly va riable (2-101 ng/ml) and were present in all breast milk samples (N=108). A significant gradient effect was observed, with greater paroxetine concentr ations found in later portions of breast milk (hind milk) than in early por tions (fore milk). No clear time course of paroxetine excretion into breast milk was demonstrated, although maternal paroxetine daily dose reliably pr edicted both trough and peak breast milk concentrations over a 24-hour peri od. in 16 mother and infant serum pairs, no detectable concentrations of pa roxetine were found in the serum of the nursing infants. Conclusions: This study extends previous data by demonstrating the presence of paroxetine in the breast milk of nursing women treated with this medication. The low conc entrations of paroxetine in infant serum and lack of any observable adverse effects after maternal use of this medication while breast-feeding paralle ls the available data on other selective serotonin reuptake inhibitors.