Levetiracetam concentrations in serum and in breast milk at birth and during lactation

Purpose: To study the pharmacokinetics of levetiracetam (LEV) at birth, during lactation, and in the nursed infant. Methods: Eight consecutive breast-feeding women with epilepsy treated with LEV twice daily and their infants were studied. Results: The mean umbilical cord serum/maternal serum ratio was 1.14 (range, 0.97-1.45) (n = 4). The mean milk/maternal serum concentration ratio was 1.00 (range, 0.76-1.33) at 3 to 5 days after delivery (n = 7). At sampling 2 weeks to 10 months after delivery (n = 5), it was similar (range, 0.85-1.38). At 3 to 5 days after delivery, the infants had very low LEV serum concentrations (< 10-15 mu M), a finding that persisted during continued breast-feeding. No malformations were detected, and in none of the infants did signs of adverse effects develop. Conclusions: Our data indicate an extensive transfer of LEV from mother to fetus and into breast milk. However, breast-fed infants had very low LEV serum concentrations, suggesting a rapid elimination of LEV.