Atomoxetine is a selective noradrenaline reuptake inhibitor that has been studied for use in the treatment of attention-deficit/hyperactivity disorder (ADHD). In vitro, ex vivo and in vivo studies have shown that atomoxetine is a highly selective antagonist of the presynaptic norepinephrine transporter with little or no affinity for other noradrenergic receptors or other neurotransmitter transporters or receptors. So far, two open-label and seven randomised, double-blind, placebo-controlled, clinical trials have been published, six in youths and three in adults. Each of these trials has shown a positive response as measured by the primary efficacy measures, the ADHD-IV Rating Scale (ADHD RS) or the Conners Adult ADHD Rating Scale (CAARS). Atomoxetine has generally been well tolerated. The most common treatment-related adverse event was decreased appetite. Atomoxetine shows no abuse potential and is not a controlled substance in the US. In November of 2002 the FDA approved atomoxetine for use in the US for the treatment of ADHD in children, adolescents and adults. Atomoxetine is the first nonstimulant approved by the FDA for the treatment of ADHD and the first medication approved for the treatment of adult ADHD.