Oral mexiletine for lidocaine-responsive neonatal epilepsy.

We report a patient with lidocaine-responsive neonatal epilepsy treated successfully with oral mexiletine. The patient was a male neonate who had seizures since 2days of age. While his seizures were refractory to phenobarbital, lamotrigine, vitamin B6, and midazolam, they were controlled by continuous lidocaine infusion. Oral mexiletine at serum levels of 0.2-0.4μg/ml was used successfully for long-term treatment of his seizures. No delay in psychomotor development was observed at the last follow-up at 20months of age. No mutation was identified in any of four genes: SCN1A, SCN1B, KCNQ2, and KCNQ3. Our patient demonstrates that oral mexiletine can be useful for long-term treatment of patients with lidocaine-responsive epilepsy.