ABSTRACT
<b>Objective: </b>The purpose of this study is to identify the problems in the adverse drug report (ADR) system in early post-marketing vigilance phase (EPM phase) in Japan.<br><b>Methods: </b>The incidence of all ADRs and the ratio of serious ADRs were compared between the new drug application phase (ND phase) and the EPM phase. The target medicines were Moxifloxacin (Avelox®tablets, 400mg), Gatifloxacin (Gatiflo®tablets, 100mg) and Prulifloxacin (Sword®tablets, 100mg).<br><b>Results: </b>The average incidence of all ADRs in the ND phase was 100-fold greater than that in the EPM phase. There were also 2-fold differences in the ratio of serious ADRs of individual medicines.<br><b>Conclusion: </b>There are several problems with the ADR system in the EPM phase in Japan. It is currently possible that the implementation of EPM will vary between in individual medicines and companies. This suggests that the present data cannot be applied universally. Thus, there is an urgent need to standardize the implementation of EPM.