Atomoxetine Treatment of Attention Deficit/Hyperactivity Disorder Symptoms in 3–6-Year-Old Children with Autism Spectrum Disorder: A Retrospective Cohort Study

Abstract

Atomoxetine is indicated for the management of attention deficit/hyperactivity disorder (ADHD) in children and adolescents aged 6 to 18 years. Few studies have assessed the safety and tolerability of atomoxetine in younger patients. This retrospective cohort study included 133 children aged 3–6 years who were diagnosed with ADHD comorbid with autism spectrum disorder (ASD). The primary endpoint was the evaluation of the safety profile of atomoxetine. In total, 50 patients (37.6%) experienced adverse events (AEs), which led to treatment discontinuation in 23 patients (17.3%). The most common AEs were gastrointestinal (24.1%), aggression or hostility (12.8%), and increased hyperactivity (9.0%). In the 23 patients who discontinued treatment, all the AEs resolved after treatment ceased. Among the 110 patients who completed at least 6 months’ treatment, atomoxetine titrated to a dose of 1.2–1.8 mg/kg/day appeared to be well tolerated and effective. The Clinical Global Impression—Improvement score improved to 1 (“very much improved”) and 2 (“much improved”) in 62.4% and 20.3% of children, respectively, at their last visit. Overall, atomoxetine appeared to be well tolerated in younger children with comorbid ADHD and ASD. Nevertheless, close patient monitoring remains essential, and the study limitations necessitate caution in generalizing these findings to broader populations. Long-term prospective studies are required.

Growing evidence of pharmacotherapy effectiveness in managing attention-deficit/hyperactivity disorder in young children with or without autism spectrum disorder: a minireview

“…In the observational study by Alsayouf et al. ( 48 ), the most common adverse events were gastrointestinal, aggression or hostility, and increased hyperactivity; in all patients who discontinued treatment due to adverse events, symptoms related to these events resolved after treatment ceased. These safety findings are consistent with those from an earlier open-label study ( 49 ).…”

“…However, longer-term treatment may be needed to fully assess atomoxetine efficacy ( 47 ). More recently, in an observational study of atomoxetine in 133 children aged 3–6 years with ADHD comorbid with ASD, atomoxetine titrated to an individualized dose of 1.2–1.8 mg/kg/day appeared to be effective, with an improvement in ADHD symptoms observed in most patients (n=110) who completed at least 6 months of treatment ( 48 ).…”