Adverse drug reaction reports regarding abnormal behavior after oseltamivir use in children as reported by consumers or healthcare professionals

Purpose: The purpose of this study was to assess the differences between consumer (patient) and healthcare professional submissions of adverse drug reaction (ADR) reports associated with certain antiviral treatments in children. Material and Methods: We extracted ADR reports for children aged <20 years who received oseltamivir or similar drugs (zanamivir and amantadine) between April 2004 and May 2020 from the Japanese Adverse Drug Event Report database. Abnormal behavior after oseltamivir administration was reported frequently in the news in November 2005, and a Dear Healthcare Professional letter about abnormal behavior after oseltamivir use was issued on March 20, 2007. We compared the number of ADR reports by three periods: (1) before the news, (2) between the news and the letter, and (3) after the letter. These reports were tabulated and analyzed after stratification according to the reporter (healthcare professionals only, patients and healthcare professionals, patients only), patient age (<10 years, 10–19 years), and ADR (abnormal behavior, other ADRs). Results: For the reports from healthcare professionals only, the number of reports per quarter associated with oseltamivir was largest during the period between the news about abnormal behavior after oseltamivir use and publication of the Dear Healthcare Professional letter. The reports from patients only about abnormal behavior after oseltamivir use were first reported after publication of the letter. The proportions of reports from patients only about abnormal behavior with oseltamivir were 81.0% and 92.2% for ages <10 and 10–19 years, respectively. A ripple effect of increasing reports was observed with zanamivir or amantadine. Conclusion: Reports from patients only might increase in response to the media more than reports from healthcare professionals only or patients and healthcare professionals do. The ADR reports from patients must be carefully assessed from the perspective of when they were reported.