Lamotrigine associated with exacerbation or de novo myoclonus in idiopathic generalized epilepsies.

Five patients with idiopathic generalized epilepsies (IGE) treated with lamotrigine (LTG) experienced exacerbation or de novo appearance of myoclonic jerks (MJ). In three patients, LTG exacerbated MJ in a dose-dependent manner with early aggravation during titration. MJ disappeared when LTG dose was decreased by 25 to 50%. In two patients, LTG exacerbated MJ in a delayed but more severe manner, with myoclonic status that only ceased after LTG withdrawal.