Excessive somnolence from aripiprazole in a child.

A 9-year-old girl was hospitalized with prolonged somnolence that began 3.5 hours after a single 15-mg dose of aripiprazole. After extensive workup, physical examinations were unremarkable, and all laboratory test results were within normal limits. The patient's extreme somnolence was attributed to aripiprazole, a new atypical antipsychotic prescribed for oppositional defiant disorder. In clinical trials, somnolence has been reported with a frequency of approximately 11%. However, the somnolence experienced by this child was severe, requiring 24-hour hospitalization for observation. Although a recent dose-finding study in 22 pediatric patients (> or = 6 yrs old) described weight-based dosages that were safe and well tolerated, dosing of aripiprazole in children has not been well established. Further studies are needed to identify optimal dosing of aripiprazole in pediatric patients.