Objective: To study the safety and efficacy of methylphenidate in children with the dual diagnosis of epilepsy and attention deficit hyperactivity disorder (ADHD).
Study design: Thirty children, aged 6.4 to 16.4 years, with epilepsy and ADHD were studied during a 4-month period. During the initial 2 months of the study, the children were treated with antiepileptic drugs (AEDs) only, and for the remaining 2 months, methylphenidate was added at a morning dose of 0.3 mg/kg. They underwent neurologic assessment, brain computed tomography, IQ testing, and assessment with the Childhood Behavior Checklist at baseline before methylphenidate therapy. Electroencephalography, AED determinations, and the continuous-performance task (CPT) test were done at baseline and after 2 months of methylphenidate therapy. A double-blind, crossover design was used to compare the effects of methylphenidate versus placebo on an electroencephalogram, AED levels, and the CPT. On the 2 days of testing, the child received AEDs and a capsule containing either placebo or methylphenidate.
Results: None of the 25 children of this sample who were seizure free had attacks while taking methylphenidate. Of the 5 children with seizures, 3 had an increase in attacks, whereas the other 2 showed no change or a reduction. There were no significant changes in AED levels or electroencephalographic findings. Methylphenidate benefited 70% of children according to parental report; methylphenidate also enhanced performance on the CPT. Side effects of methylphenidate were mild and transient.
Conclusion: Methylphenidate is effective in treating children with epilepsy and ADHD and safe in children who are seizure free. Caution is warranted for those still having seizures while receiving AED therapy.