Low-dose phenobarbital for epilepsy with myoclonic absences: A case report

Epilepsy with myoclonic absences (EMA) is a rare childhood-onset syndrome characterized by absences of responsiveness accompanied by bilateral rhythmic clonic-like myoclonic jerks. Herein, we describe the case of a child with EMA, resistant to multiple commonly used antiepileptic drugs, in whom low-dose phenobarbital unexpectedly achieved complete remission of epilepsy.

A 10-year-old boy was referred to our hospital because of pharmaco-resistant frequent myoclonic absence seizures (MASs) and occasional generalized tonic-clonic seizures (GTCSs) that had commenced at the age of 7 years. Antiepileptic drugs including valproate sodium (VPA), levetiracetam, ethosuximide (ESM), clobazam, zonisamide, topiramate, clonazepam and lamotrigine were tested without significant effects. At the age of 8 years, phenobarbital was added to the VPA and ESM and increased to 1.2 mg/kg/day (blood concentration 8.6 µg/mL), which suppressed MASs completely within 1 month, and epileptic discharges on electroencephalography (EEG) within 5 months. To date, the boy has been seizure-free with normal EEG for 2 years.

Phenobarbital is a potential therapeutic option for pharmaco-resistant EMA.