Therapeutic monitoring of lacosamide, perampanel, and zonisamide during breastfeeding

To provide additional information on the transport of the new anti-seizure medications lacosamide, perampanel, and zonisamide in breast milk and breastfed infants. Between 2013 and 2022, concentrations of anti-seizure medications were measured in six women with epilepsy (each drug in two patients) using high-performance liquid chromatography. Additionally, concentrations were determined after two consecutive pregnancies in women receiving lacosamide and one woman receiving zonisamide. In all cases, anti-seizure medication concentrations were measured in the maternal serum and breast milk, and five cases, in the infant serum. For lacosamide, the ratios of breast milk/maternal serum concentration varied between 0.77 and 0.93, the ratios of infant/maternal serum concentrations were 0.16 and 0.35, and the ratios of infant serum/milk concentrations were 0.21 and 0.38. For perampanel, the ratios of breast milk/maternal serum concentration were 0.01 and 0.10 and the ratio of infant/maternal serum concentration was 0.36. For zonisamide, the ratios of breast milk/maternal serum concentration varied between 0.76 and 1.26, the ratios of infant/maternal serum concentrations between 0.44 and 0.85, and the ratios of infant serum/milk concentrations between 0.55 and 1.05. Breastfeeding is recommended for women using lacosamide, perampanel, and zonisamide. However, the actual exposure can only be accurately evaluated by determining the serum concentration of anti-seizure medication in breastfed infants.