Aims: The main purpose of this first atomoxetine study in Japanese adults with attention-deficit/hyperactivity disorder (ADHD) was to investigate the tolerability of an 8-week treatment regimen.
Methods: This was an open-label, dose escalation study conducted in 45 Japanese patients aged at least 18 years with DSM-IV-defined ADHD. Patients received atomoxetine orally for 8 weeks. Atomoxetine administration was started at 40 mg/day (7 days), and subsequently increased to a maximum dose of 120 mg/day. Tolerability was assessed by discontinuation rate due to adverse events. Adverse events, laboratory tests, vital signs and electrocardiograms were collected. In addition, ADHD symptoms were assessed by using the Japanese version of the Conners' Adult ADHD Rating Scale-Investigator Rated: Screening Version (CAARS-Inv:SV) scores.
Results: Thirty-nine patients completed the study period. Atomoxetine was well tolerated with a 6.7% (3/45) discontinuation rate due to nausea, malaise and anorexia. The most commonly reported adverse events were nausea, nasopharyngitis and headache; there were no unexpected safety concerns. No deaths or serious adverse events were reported. Mean CAARS-Inv:SV-J total ADHD symptom scores decreased in a time-dependent manner; the mean change from baseline to endpoint was −15.0 (P < 0.001).
Conclusions: This study showed that atomoxetine was well tolerated in these patients and suggested that atomoxetine at a maximum dose of 120 mg/day would be safe in Japanese ADHD patients.