Trends in Anti-Influenza Drug Prescription and Adverse Drug Reaction Reporting After the Lifting of Oseltamivir Prescribing Restrictions in Pediatric Outpatients: An Ecological Study Using the MDV Analyzer® And the Japanese Adverse Drug Event Report Database

Abnormal behavior after oseltamivir administration has been reported in the media; in 2007, the package insert for oseltamivir phosphate was revised to restrict its administration to individuals aged over 10 years. However, in 2018, the age limitation specified in the package insert was removed. Here, we evaluated the trends in anti-influenza drug prescription and adverse drug reactions (ADRs) reported in pediatric outpatients after revising the oseltamivir package insert as an ecological study. Anti-influenza drug prescriptions for pediatric outpatients with influenza aged 0–19 years were downloaded from the acute Diagnosis Procedure Combination hospital databases using the MDV analyzer®. ADR reports on anti-influenza drug prescription among patients aged 0–20 years in the Japanese Adverse Drug Event Report database were downloaded from the Pharmaceutical and Medical Devices Agency website. Data were collected during the 2016/2017 and 2019/2020 influenza seasons. During the influenza epidemic season (January–March), the percentage of oseltamivir prescriptions for patients with influenza aged 10–19 years tripled after the revision of the oseltamivir package insert (9.3