Introduction: Atomoxetine (Strattera) is the first non-stimulant drug to be approved for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD) in children 6 years of age and adolescents. Atomoxetine is a highly specific inhibitor of the presynaptic norepinephrine transporter, with minimal affinity for other transporters or other neurotransmitter receptors. The target dose is 1.2 mg/kg, in a once- or twice-daily oral administration.

Clinical data: Six randomized, double blind, placebo-controlled clinical trials have demonstrated that atomoxetine was more effective than placebo for the treatment of children and adolescents with ADHD. All these trials have shown a consistent improvement in the ADHD rating scale (ADHD-RS) from baseline in the patients treated with atomoxetine, compared with that of the placebo group. The improvement of ADHD symptoms was confirmed by the other secondary efficacy measures (the Clinical Global Impression, CGI, the Conners ADHD rating scale/parent, teacher). The duration of action of atomoxetine on ADHD symptoms extended throughout the waking hours, and the drug effects persisted up to the next morning with a single morning dose. Significant improvements were also observed with atomoxetine compared to placebo, in several aspects of the quality of life measurement (social and family functioning), and the child's self-esteem. In addition, in patients who responded favourably to initial treatment, atomoxetine was shown to be superior to placebo in maintaining a long term-response, up to 18 months. Atomoxetine was effective and safe, both in young children and adolescents with ADHD. Preliminary data also support the potential efficacy of atomoxetine in managing patients with ADHD and comorbid conditions, such as tic disorders, oppositional-defiant and conduct disorders.

Discussion: As of June 2004, over 3,000 children and adolescents have been enrolled in clinical trials of atomoxetine, with about 1,200 of them treated for more than 1 year and about 400 of them treated for more than 2 years. Atomoxetine was well tolerated in most individuals, the two more common adverse events reported were gastro-intestinal disorders and decreased appetite. These side effects were generally noted to be transient. No significant changes in weight and height gain was reported over the long-term follow-up. There was no evidence of symptoms rebound and no evidence of an acute discontinuation syndrome when discontinuing treatment. In addition, given the mechanism of action of atomoxetine in the central nervous system, and lack of subjective, physiological and psychomotor effects reported in experimental conditions, it is unlikely that atomoxetine would have abuse potential.

Conclusion: Results from clinical trials demonstrated that atomoxetine is effective and well tolerated for the acute and long-term treatment of children and adolescents suffering from ADHD. Atomoxetine should be considered as a new interesting pharmacological option in the treatment of ADHD in association with non pharmacological therapeutic interventions.