Fast vs. Slow Switching from Stimulants to Atomoxetine in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder

Objective: To compare fast versus slow switching from stimulants to atomoxetine (ATX) in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Methods: This was a randomized, controlled, open-label study in 6-16-year-old ADHD patients, previously treated with stimulants and cross-titrated (fast switch, over 2 weeks, or slow switch, over 10 weeks) to ATX because of unsatisfactory response and/or adverse events. Study duration was 14 weeks with an ATX standard target dose of 1.2 mg/kg/day. Primary measure was the change from baseline in the investigator-rated ADHD-Rating Scale (ADHD-RS) at weeks 2 and 10. Secondary measures included Global Impression of Perceived Difficulties (GIPD) and Child Health and Illness Profile-Child Edition (CHIP-CE). Results: The majority of the 111 patients were male (83.8%, n = 93) and mean (SD) age was 11.5 (2.38) years. Mean baseline ADHD-RS total score was 36.0 in the fast and 38.0 in the slow group. Adjusted mean change after 2 weeks was -8.1 (-10.1; -6.1) in the fast and -8.0 (-9.9; -6.0) in the slow group (p = 0.927), and after 10 weeks -15.0 (-17.4; -12.6) and -14.3 (-16.7; -12.0), respectively, (p = 0.692). GIPD scores did not show differences between groups. Significant differences at week 10 were found in the CHIP-CE achievement domain favoring slow (p = 0.036) and the comfort domain favoring fast cross-titration (p = 0.030). No significant differences were found for adverse events, and differences for systolic blood pressure (BP) and weight were not considered clinically relevant. Conclusions: ADHD-RS and GIPD scores improved in both switching groups. No clinically relevant differences between fast and slow switching from stimulants to ATX were found.