Abstracts

Sparse information exists about the overall effectiveness and dose response curve characteristics for initial antiepileptic drug (AED) monotherapy in children with partial onset seizures. The purpose of this work is to characterize the effectiveness and dose response curve characteristics of carbamazepine (CBZ) initial monotherapy in a cohort of consecutive children with partial onset epilepsy., A cohort of 100 consecutive children (1-18 years of age) with newly diagnosed partial onset epilepsy treated with CBZ as initial monotherapy was identified from the New Onset Seizure Clinic at Cincinnati Children[apos]s Hospital Medical Center. Information from the history, physical examination, MRI, and EEG were used to classify the patient[apos]s epilepsy and etiology. Seizure control, adherence, and adverse events were recorded at each visit. CBZ responsiveness was defined as seizure freedom for at least 12-months on a stable dose of CBZ monotherapy or breakthrough seizures only with missed doses in patients with evidence of compliance from random levels. Non-responsiveness was defined as the addition or substitution of a second AED because of continued seizures and/or intolerable adverse events., Of the 100 patients studied, 55 became seizure free on CBZ monotherapy, 10 did not tolerate CBZ within the first 3 months of therapy either due to hypersensitivity or intolerable side effects and 35 continued to have seizures. The mean dose in seizure-free children was 11.1 mg/kg/day (standard deviation 3.4 mg/kg/d). The majority of these children responded at the initial dose. Following achievement of the initial target dose 36% of all patients stopped having seizures. There was a weak but statistically significant correlation between age at time of treatment and dose used to control seizures. In children under 12 years age (n=44) the average daily dose in seizure-free children was 11.8 [plusmn] 3.4 mg/kg/d. In those 12 years of age and over (n=11) the average dose was 9.0 [plusmn] 3.4 mg/kg/d in seizure-free children (p[lt]0.05). The data followed a normal distribution and from this it was determined that over 95% of children [lt] 12 years will respond by 17.5 mg/kg/d and 95% children 12 and over will respond by 15 mg/kg/d., Slightly over half (55%) of children with newly diagnosed partial onset epilepsy become seizure free with initial CBZ monotherapy. A considerable percentage (over one-third of these) became seizure free as soon as they began taking CBZ. The CBZ dose response curve reaches its upper plateau at doses lower than expected. Children under 12 years of age who continue to have seizures at CBZ doses above 17.5 mg/kg/d and those [ge]12 years who continue to have seizures at 15 mg/kg/d are very unlikely to respond to CBZ. Other treatments should be considered when seizures continue at CBZ doses above this even if the child is not experiencing intolerable dose related side-effects., (Supported by CCHMC Trustee Grant.)