© 2018, Children's Hospital, Zhejiang University School of Medicine. Background: Off-label use of psychotropic prescriptions for pediatric patients has been increasing in Japan. This study sought to clarify pediatric patients’ off-label use of psychotropics approved only for adults in Japan. Methods: This retrospective study on psychotropic utilization employed a pharmaceutical health insurance claims database supplied by a pharmacy for the fiscal year 2016. Seven psychotropic drugs were examined. For each drug, we calculated the proportion of patients aged < 16 years or who were under the approved age limit set in the United States out of all patients. The maximum daily dose of each drug within the study period was plotted by age. Results: Data of 45,715 patients (female: 26,799, male: 18,916) with 331,920 prescriptions were examined in this study. For each drug, the proportion of pediatric patients aged < 16 years ranged from 0.15 to 1.1%, while the proportion of those under the approved age limit in the United States ranged from 0 to 0.27%. Olanzapine had the highest reported proportion. No drugs other than olanzapine were taken under the approved age limit in the United States. Conclusions: We identified the pediatric off-label use of psychotropics that were limited to adult use in Japan. The results indicated the possibility of referring to international guidelines or evidence in clinical practice, but these factors do not discount the existing problems with off-label use. More clinical trials within the pediatric population in Japan are needed to address the issue of off-label use and obtain useful and reliable information in the package inserts for rational use in future pediatric patients.
