Ethosuximide is effective in the treatment of epileptic negative myoclonusin childhood partial epilepsy

The aim of our study was to evaluate the effectiveness of ethosuximide in t he treatment of epileptic negative myoclonus, a motor disorder that can occ ur in childhood partial epilepsy. We introduced ethosuximide in nine patien ts with partial epilepsy of varying etiology (idiopathic, cryptogenic, symp tomatic) who presented with epileptic negative myoclonus. The drug was adde d to the patients' preexisting antiepileptic drugs, which were maintained u nchanged for the following 6 months. Epileptic negative myoclonus disappear ed in all patients 15 to 30 days after ethosuximide was started. Plasma eth osuximide levels ranged from 55 to 89 mu g/mL. The clinical response was no t influenced by the patients' preexisting treatment or by the etiology of t he epilepsy. No side effects were observed, and none of the patients presen ted a recurrence of epileptic negative myoclonus during follow-up. Furtherm ore, in five patients we observed the disappearance of partial seizures; in the remaining patients seizures were reduced by more than 75%. Electroence phalograms showed a decrement or disappearance of focal paroxysmal abnormal ities. Our results suggest that ethosuximide is effective in the treatment of epileptic negative myoclonus and that it should be considered as a first -choice drug in the treatment of this motor disorder.