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 approximately 8 weeks. Primary efficacy assessment was the comparison of response rates (> or =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.