High-dose atomoxetine treatment of ADHD in youths with limited response to standard doses

Objective: To assess the utility and tolerability of higher than standard atomoxetine doses to treat attention -deficit/ hyperactivity disorder (ADHD). Method: Two randomized, double-blind trials of atomoxetine nonresponders ages 6 to 16 years were conducted comparing continued treatment with same-dose atomoxetine to treatment using greater than standard efficacious doses (study 1: up to 3.0 mg . kg(-1). day(-1); study2: up to 2.4mg . kg(-1) . day(-1)). Results: The primary outcome measure for both studies was mean ADHD Rating Scale (ADHD RS) total score. Forstudy 1 (N= 122), decreases in ADHD RS total scores were not significantly different between treatment groups (mean change [SD]: continued same dose, -8.9 [11.2]; high dose, -9.8 [13.1]; p=.595). Likewise, forstudy2 (N=125), treatment groups did not differ(mean change [SD]: continued same dose, -6.2 [12.2]; high dose, -8.9 [10.0], p=.110). Tolerability was not significantly different between the continued same-dose and high-dose groups. Conclusions: These studies provide evidence that current dose recommendations are appropriate for most patients, suggesting no systematic advantage to increasing atomoxetine doses beyond current guidelines. In both studies, continued treatment, whether at a higher dose or the previous dose, was associated with improved outcomes in patients who demonstrated incomplete/inadequate response to acute ADHD treatment, although without a placebo arm, we cannot rule out the possibility that expectancy played a role in symptom improvement.