Lacosamide serum concentrations during pregnancy

Still considered a new ASD, teratogenicity from lacosamide (LCM) exposure during pregnancy is unknown. LCM metabolism through several cytochrome P450 enzymes and minor glucuronidation metabolism in the liver may increase during pregnancy and theoretically lead to lower LCM levels during pregnancy and the risk of increased seizures. Our objective was to determine the impact of pregnancy on serum LCM levels in a series of women with epilepsy (WWE). We identified seven pregnancies with exposure to LCM with at least one level drawn during pregnancy. Patient ages ranged from 18 to 38 years (mean 26.4 years) and total daily doses of LCM ranged from 200 to 600 mg/day. Two patients had increased dose adjustments in response to breakthrough seizures. Dose normalized concentrations (DNC) showed an overall decrease over time through each trimester (p = 0.002) and significantly lower during trimester 2 and 3 (p = 0.001 and p = 0.004, respectively) compared to pre-pregnancy levels. There were no significant changes in seizure frequency and none of the neonates had teratogenic findings at time of birth. We are the first to report a case series on the changes in LCM levels during pregnancy with significant decreased LCM DNC levels during the second and third trimesters in comparison to pre-pregnancy values.