Therapeutic drug monitoring of lacosamide as add-on treatment in a neonate with therapy-resistant epilepsy due to SCN2A mutation: a case report

Lacosamide is registered for the treatment of (partial-onset) seizures in adults and children > 2 years of age, with a recommended maximum dose of 12 mg kg-1 in two doses. It is generally well tolerated. The use of lacosamide in neonates is off-label. We present the first case of a neonatal patient with refractory epilepsy who was started on lacosamide with monitoring of serial serum levels. We present a case of a prematurely (33 weeks) born Dutch, male neonate with refractory seizures despite multiple anti-epileptic drugs due to a de novo SCN2A mutation. Lacosamide was added, and serial serum trough levels were measured to optimize the dose. Based on the available literature, the dose needed to achieve a therapeutic serum trough level in our patient was much higher than expected, with a dose of 22 mg kg-1 in 4 doses. No side effects were observed. In specific cases in the neonatal population, lacosamide is safe and well tolerated and should be considered as a treatment option under strict surveillance of serum trough levels and cardiac monitoring. Higher doses might be needed to achieve a therapeutic serum trough level. Further research is needed to generalize these results and develop adjusted dose guidelines in the neonatal population.