Abstract
OBJECTIVE: The purpose of this study was to investigate whether the availability of both dextroamphetamine and methylphenidate provides an opportunity to minimize adverse events in a pediatric attention-deficit/hyperactivity disorder (ADHD) stimulant trial. METHODS: Thirty-six medication-naïve children 9-14 years of age, diagnosed with ADHD, were enrolled for 6 weeks in a crossover trial, with 2 weeks of methylphenidate, dextroamphetamine, and a placebo in a randomly assigned, counterbalanced sequence. Barkley's Side-Effect Rating Scale (SERS), rated by parents, was used to assess adverse events. SERS were available for 34 children, and data were analyzed both at the group and the single-subject level. RESULTS: The side-effect profiles of dextroamphetamine and methylphenidate appeared similar at the group level. Overall, insomnia and decreased appetite were the only adverse events associated with the stimulants as compared with placebo. No significant increase from placebo to stimulant conditions was detected on SERS items reflecting emotional symptoms. Furthermore, dextroamphetamine and methylphenidate did not differ from each other on any SERS item, except that dextroamphetamine was associated with higher severity of "insomnia" and a higher prevalence of "unusually happy." Single-subject analyses showed that one or more adverse events were reported in 14 children (41%), and were evenly distributed between those with dextroamphetamine as the drug that showed the greatest reduction in their ADHD symptoms ("best drug") and those with methylphenidate as their best drug. Among children in whom both stimulants were associated with a decrease in ADHD symptoms, a clinically valid difference between the two stimulants in total adverse events score was found in 7 (39%) of the 18 cases. In these children, the availability of both stimulants provided an opportunity to minimize adverse events, while maintaining a reduction in ADHD symptoms. CONCLUSIONS: The availability of both dextroamphetamine and methylphenidate may contribute to minimize adverse events in a subsample of children in pediatric ADHD stimulant trials. CLINICAL TRIALS REGISTRY: The study was first registered in clinical trials September 28, 2010. Clinical Trials.gov Identifier: NCT01220440.