Abstracts

RATIONALE: VGB is reported effective in European studies of IS, most using 100-200mg/k/d. A multicenter study in the USA has reported fewer responses. We report our experience with VGB for IS. METHODS: We reviewed children receiving VGB for IS since 2/98. All families obtained VGB abroad. None were enrolled in a formal study. Management was clinical. We abstracted etiology, previous treatments, VGB dosage, responses to treatment, adverse effects, other seizure types. RESULTS: 20 subjects were identified. Age of onset of IS varied from 1 to 9 months; age at treatment from 1-48 months, with both cryptogenic and various secondary etiologies. Prior IS treatments included none (11), ACTH, VPA, ketogenic diet, topiramate, B6, clonazepam. Concomitant AEDs included phenobarbital (3), TPM (2), clonazepam (1), tiagabine (1). Parents were instructed to begin VGB at the lowest practical dose, (1/4 or 1/2 of a 500 mg tablet on the first day, increasing by 1/4 or 1/2 tablet daily to 100 mg/k/d). If response occurred at a lower dose, they were instructed to continue it. 12 of 20 responded with complete cessation of IS and resolution of hypsarrhythmia, at doses ranging from 25-135 mg/kg/d (median 58mg/k/d). Clinical response was often seen after 1-2 doses. No child responded after initial non-response of ?4weeks. Partial responses were seen in 6. 2 older children had reproducible decreases in longstanding IS (65 and 125 mg/k/d). Four others had decrease in IS but continued hypsarrhythmia (40-142mg/k/d). Two had no response (111-125mg/k/d). One child was found to have pigmentary retinopathy after starting VGB, and the drug was withdrawn, but was clinically blind prior to starting VGB. 6 had eye or optic nerve anomaly or cortical blindness prior to starting VGB; none worsened. The rest had normal eye exams before, during and after VGB. Additional seizure types developed after initial response of IS to VGB in 3; Increased VGB had no benefit. CONCLUSIONS: Response to VGB in IS is dose-independent. IS responded to VGB both as initial treatment and after failing other treatments. Response was independent of etiology. There was 1 case of pigmentary retinopathy, possibly related to VGB, but no other adverse effects.