Does One More Medication Help? Effect of Adding Another Anticonvulsant in Childhood Epilepsy

Objectives: To study adding an anticonvulsant in children with uncontrolled epilepsy on >= 1 appropriate anticonvulsants. Methods: Chart review, patients with intractable epilepsy in a neurology clinic July 1, 2004 to December 31, 2007. Inclusion: Children on >= 1 stable anticonvulsant who had a second, third, or fourth anticonvulsant added. Exclusions: Noncompliance, subtherapeutic doses, and/or serum anticonvulsant levels, inappropriate anticonvulsant for seizure type, inadequate documentation, infantile spasms, or significant dosage changes in the baseline anticonvulsant(s) over the follow-up period. Patients were followed until further therapeutic changes occurred or September 30, 2008, whichever came first. Outcome: >= 50% decrease in seizure frequency. Results: Charts reviewed: 1886. Patients who met criteria: 84. Time to assessment: 4 weeks to 42 months (median 7 months). >= 50% reduction in seizure frequency: 35 of 52 patients with second agent added; 5 of 30 patients with third agent added (P = .0001). Conclusions: Worthwhile seizure reduction is reasonably likely with the addition of a second anticonvulsant, but much less likely with the addition of third anticonvulsant.