A pilot study for augmenting atomoxetine with methylphenidate: safety of concomitant therapy in children with attention-deficit/hyperactivity disorder

BACKGROUND This study examined augmenting atomoxetine with extended-release methylphenidate in children whose attention-deficit/hyperactivity disorder (ADHD) previously failed to respond adequately to stimulant medication. METHODS Children with ADHD and prior stimulant treatment (N = 25) received atomoxetine (1.2 mg/kg/day) plus placebo. After 4 weeks, patients who were responders (n = 4) were continued on atomoxetine/placebo while remaining patients were randomly assigned to either methylphenidate (ATX/MPH) (1.1 mg/kg/day) or placebo augmentation (ATX/PB) for another 6 weeks. Patients and sites were blind to timing of active augmentation. Safety measures included vital signs, weight, and adverse events. Efficacy was assessed by ADHD rating scales. RESULTS Categorical increases in vital signs occurred for 5 patients (3 patients in ATX/MPH, 2 patients in ATX/PBO). Sixteen percent discontinued the study due to AE, but no difference between augmentation groups. Atomoxetine treatment was efficacious on outcome measures (P <or= .001), but methylphenidate did not enhance response. CONCLUSION Methylphenidate appears to be safely combined with atomoxetine, but conclusions limited by small sample. With atomoxetine treatment, 43% of patients achieved normalization on ADHD ratings.