ABSTRACT
BACKGROUND: Attention-Deficit/Hyperactivity Disorder (ADHD) is a disorder characterized by hyperactivity, impulsiveness, and inattention that affects 4% of adults. Atomoxetine hydrochloride is an FDA-approved treatment for adult ADHD, but no studies have clarified whether there are advantages to once versus twice daily dosing. METHODS: This randomized, double-blind, multicenter study compared safety and tolerability of 80 mg atomoxetine QD versus 40 mg atomoxetine BID in 218 adults with ADHD. Treatment-emergent adverse events (TEAEs), laboratory values, vital signs, weight, electrocardiograms, scores on the Arizona Sexual Experiences Scale, and efficacy (using the Conners' ADHD Rating Scale-Investigator Rated: Screening Version) were assessed. RESULTS: The overall incidence for any one TEAE was low. There was no significant treatment group difference in likelihood of patients experiencing >/=1 of the four most commonly observed TEAEs (dry mouth, insomnia, nausea, and erectile dysfunction). Frequency of nausea was significantly lower in the 40 mg BID group (16.4%) than the 80 mg QD group (32.4%; p = .007). There were no unexpected safety results. Although both QD and BID treatments were efficacious, the reduction in scores was greater for BID treatment. CONCLUSIONS: Data indicate both dosing strategies are safe, well tolerated, and efficacious in the treatment of adult ADHD. Changes in dosing strategy are unlikely to be accompanied by safety risks, implying that there is room for prescribers to use discretion and to base dosing strategies on individual factors.
