Absence seizures aggravated by valproic acid

Purpose: To report on pediatric patients with absence epilepsy who experien ced absence seizure aggravation while receiving valproic acid (VPA). Methods: The charts of all children from four pediatric epilepsy clinics re ceiving VPA for absence epilepsy were reviewed. Patients were evaluated and followed up between 1994 and 2000. Results: Eight cases (six boys) of absence seizure aggravation were detecte d. Mean age at seizure onset was 5.8 years (range, 3-12 years). Six patient s had simple absence seizures, one had myoclonic absences, and one had abse nces with automatisms. The electroencephalogram in all cases depicted gener alized 3-Hz spike-and-wave activities. All eight patients experienced an in crease in the frequency of absence seizures within days of VPA introduction . Dose increments resulted in further seizure aggravation. Serum levels of VPA were within therapeutic range in all patients. No case was attributed t o VPA-induced encephalopathy. All patients improved on VPA discontinuation. In five children, VPA was reintroduced, resulting in further seizure aggra vation. Conclusions: VPA can occasionally provoke absence seizure aggravation in pa tients with absence epilepsy.