Comparisons between the Prescription Share Rate of Tablet Forms of Authorized and Conventional Generic Drugs using National Database of Japan

抄録

Within Japan, national medical costs are continuing to increase owing to the aging population and advances in medical technologies. The market share occupied by generic drugs is still low compared with other countries. We investigated trends in the use of generic drugs (tablets) with introduced authorized generics (AGs) using National Database of Japan (NDB) Open Data. We evaluated the impact of introducing AGs on the transition to generic drugs. We found that more than 80% of drugs with AGs had generic usage rates exceeding 70%. AGs are often used to treat chronic diseases, such as hypertension. Branded drug manufacturer-approved AGs are considered associated with less negative perceptions; however, despite this, it remains difficult to say whether the introduction of AGs has promoted the use of generic drugs overall. Furthermore, we inferred that the timing of introduction to the market is vital for AGs. Considering the tight medical financial situation in Japan, shifting to the use of generic drugs, including AGs, would be favorable after patents for branded drugs expire. It is also necessary to conduct a detailed analysis of trends in the use of generic drugs, including AGs.