Disabling erratic myoclonus during lamotrigine therapy with high serum level - Report of two cases

Wt present two patients with epilepsy who experienced disabling myoclonic j erks during lamotrigine treatment. Both were young males who had intractabl e cryptogenic generalized epilepsy since childhood. They received a lamotri gine-valproate combination resulting in an excellent improvement: however, after 2-3 years of therapy, both patients were hospitalized because of cont inuous disabling myoclonic jerks. The dosage of lamotrigine was the same be fore and at the onset of myoclonus. When the severe myoclonus started, both patients had a higher serum lamotrigine level (16.5 and 17.7 mg/L, respect ively) than in previous findings. Disabling myoclonus was also present duri ng lamotrigine monotherapy with 15 mg/L serum level. Lamotrigine may severe ly worsen myoclonic phenomena in generalized epilepsies, in which adverse e vents may be dependent on drug serum level.