Ezogabine treatment of childhood absence epilepsy

Abstract

Generalised-onset absence seizures can be resistant to treatment with currently available antiepileptic drugs. Ezogabine (retigabine), a potassium channel opener, is approved for the treatment of focal-onset seizures. This is a case report of an adult with childhood absence epilepsy whose daily absence seizures ceased with adjunctive ezogabine. A 59-year-old woman, with a history of typical absence seizures since the age of 6 years, had multiple seizures daily despite trials of over 11 antiepileptic drugs. While taking lamotrigine and zonisamide, ezogabine at 50mg daily was added. The dose was slowly increased and once a total dose of only 200mg/day was reached, she became seizure-free for three months. After subsequently discontinuing zonisamide, absence seizures returned. Further increasing the ezogabine to 400mg/day, in addition to lamotrigine, did not restore seizure freedom, but adding back zonisamide at half dose again reduced their frequency. Ezogabine at low dose, added to lamotrigine and zonisamide, led to sustained absence seizure freedom. The return of seizures after zonisamide discontinuation suggests that the seizure freedom may have been the result of the different mechanisms of action of the antiepileptic drugs.