Atomoxetine versus Methylphenidate in Paediatric Outpatients with Attention Deficit Hyperactivity Disorder: A Randomized, Double-Blind Comparison Trial

Abstract

Objective: To (i) test whether atomoxetine is non-inferior to methylphenidate in treating symptoms of attention deficit hyperactivity disorder (ADHD) in paediatric patients; and (ii) determine the tolerability of the two drugs. Method: This double-blind study was conducted in 6- to 16-year-old outpatients with ADHD (DSM-IV) in China, Korea and Mexico (January–October 2004). Patients were randomly assigned to once-daily atomoxetine (0.8–1.8 mg kg−1 day−1; n = 164) or twice-daily methylphenidate (0.2–0.6 mg kg−1 day−1; n = 166) for ∼8 weeks. Primary efficacy assessment was the comparison of response rates (≥40% reduction from baseline to end point in total score) on the Attention Deficit Hyperactivity Disorder Rating Scale-IV-Parent Version: Investigator-Administered and -Scored. Tolerability measures included, but were not limited to, the assessment of treatment-emergent adverse events (TEAEs) and weight. Results: Atomoxetine was non-inferior to methylphenidate in improving ADHD symptoms based on response rates (atomoxetine, 77.4%; methylphenidate, 81.5%; one-sided 95% lower confidence limit = −11.7%, p = 0.404). Treatment-emergent adverse effects experienced significantly more frequently in the atomoxetine group, compared with the methylphenidate group, included anorexia (37.2% vs. 25.3%; p = 0.024), nausea (20.1% vs. 10.2%; p = 0.014), somnolence (26.2% vs. 3.6%; p <0.001), dizziness (15.2% vs. 7.2%; p = 0.024) and vomiting (11.6% vs. 3.6%; p = 0.007), most of which were of mild or moderate severity. Atomoxetine-treated patients experienced a small but significantly greater mean weight loss from baseline to end point than methylphenidate-treated patients (−1.2 kg vs. −0.4 kg; p <0.001). Conclusions: This study suggests that atomoxetine is non-inferior to methylphenidate in the improvement of ADHD symptoms in paediatric outpatients. Although both of the drugs were well tolerated, atomoxetine was associated with a higher incidence of TEAEs than methylphenidate.