Effect of two different methods of initiating atomoxetine on the adverse event profile of atomoxetine

Objective: To compare the effects of two different methods for initiating atomoxetine in terms of the incidence of early adverse events. Method: Data on atomoxetine treatment-emergent adverse events in youths, ages 6 to 18 years, were analyzed from five randomized, double-blind, placebo-controlled, acute-phase studies. Two studies involve once-daily dosing and titration to 1.2 mg/kg/day over 3 days (fast/once daily, n = 234) and three involve twice-daily dosing and titration to a dose of 1.2 mg/kg/day over at least 2 weeks (slow/twice daily, n = 213). Results: During the first 2 weeks of treatment, fast/once daily titration patients showed higher rates of spontaneously reported adverse events than patients in the slow/twice daily titration group. This included decreased appetite (14.3% versus 8.0%, p= .036) and somnolence (14.3% versus 4.2%, p < .001). Patients in the slow/twice daily group showed higher rates of headache (7.4% versus 16.9%, p = .003). Analysis of the studies' overall acute treatment phases revealed significantly higher rates in the fast/once daily group only for somnolence. No significant differences were seen in completion rates or reasons for discontinuation. Conclusions: When starting atomoxetine, the risk of adverse events within the first few weeks of treatment may be lower if patients are dosed twice daily and titrated to the 1.2 mg/kg/day total daily dose over the first week.