ObjectiveTo investigate the impact of national implementation of age restriction on fluoroquinolone prescription in children and adolescents.MethodsData collected from the database of Health Insurance Review and Assessment Service in South Korea, a national health insurance system to analyze fluoroquinolone prescribing practice in children and adolescents younger than 18 years, between 2007 and 2015. The age restriction was implemented in December 2009. The annual prescription rate of FQ per 100,000 person-years was calculated and an autoregressive model was used to predict the prescription pattern if an intervention had not occurred.ResultsA total of 505,859 children received systemic fluoroquinolone during the study period—297,054 ciprofloxacin, and 208,805 levofloxacin. After implementation of the drug utilization review program, the annual prescription rate for ciprofloxacin declined by 97.5% (from 840 to 21 per 100,000 person-years, P < 0.001), and for levofloxacin by 96.4% (from 598 to 11 per 100,000 person-years, P < 0.001). The decline was more dramatic in the outpatient setting than in the inpatient setting for both drugs.ConclusionThe dramatic and sustained decline in prescription number and change in prescription pattern after the regulatory action suggests that the implementation under drug utilization review program was successful in controlling excessive and inappropriate use of fluoroquinolones in children, possibly guiding towards more judicious and selective prescription behavior.