Estimation of rac-amisulpride transfer into milk and of infant dose via milk during its use in a lactating woman with bipolar disorder and schizophrenia.

This case describes the transfer of the antipsychotic drug amisulpride into milk and the estimation of infant exposure via breastfeeding. The dyad investigated was a 28-year-old lactating woman and her 13-month-old daughter. The woman had been taking 400 mg of amisulpride daily for 9 days and provided eight milk samples and one blood sample over a 24-hour dose interval. Amisulpride concentrations in these samples were measured by high-performance liquid chromatography, and infant dose was calculated by standard methods. The infant's health and progress were evaluated by a neonatal pediatrician. Transfer of amisulpride into milk was high, with a milk:plasma distribution ratio of 19.5 (5,188 μg/L in milk and 266 μg/L in plasma). The average amisulpride concentration in milk was 3,562 μg/L, which, when multiplied by an average milk intake of 0.15 L/kg/day, gave an absolute infant dose of 534 μg/kg/day. The relative infant dose was 10.7% of the maternal weight-adjusted dose (5,000 μg/kg/day), which is slightly above the usual 10% safety recommendation. The infant was in good health with an appropriate Denver development score for her age. She showed no acute drug-related adverse effects. Given that the infant had already benefited from 13 months of breastfeeding, that amisulpride has potential adverse effects, and that its relative infant dose was 10.7%, we recommended cessation of breastfeeding in the near-term.