Comparing the Dosing Period in Package Inserts of Antimicrobial Agents Between Japan and the United States

Introduction: The duration of antimicrobial therapy is a critical evaluation index of antimicrobial stewardship (AS). The inclusion of the dosing period on package inserts provides a strong reason for clinical intervention by pharmacists in cases where physicians prescribe inappropriate dosing periods. This study investigated differences in the description of dosing periods in antimicrobial package inserts between Japan and the U.S. Methods: We conducted a survey comparing differences in the dosing period of oral and injectable antimicrobials approved and marketed in Japan and the U.S. as of May 1, 2021. The Fisher exact test was used to compare the presence or absence of a description of the dosing period on the package insert between these two countries. Results: We evaluated 69 antimicrobial agents, of which 34 were oral; and 35 were injectable agents. In Japan, 20 (29.0%) of the antimicrobials had package inserts stating the dosing periods, compared with 58 (84.1%) in the U.S. (p < 0.001). Conclusions: It was found that the information on the duration of administration was missing from the package insert in Japan compared to the U.S. Lack of information on the duration of administration may lead to long-term administration by the treating physician and also make it difficult for the pharmacist to inquire about the administration. It is expected that the inclusion of scientifically-based dosing periods in all package inserts will promote AS among physicians and pharmacists who are not specialists in infectious disease therapy.