Glucagon and insulin prescribing trends and cost implications in Japan: a 10-year analysis using the National...

In 2020, ready-to-use nasal glucagon was introduced in Japan, enabling more rapid caregiver response during episodes of severe hypoglycemia. However, nationwide prescribing patterns and changes in drug expenditures for glucagon products remain unclear. Additionally, updated information on insulin formulations, which are major contributors to hypoglycemia, is lacking. Understanding the recent trends in these medications is, therefore, necessary.

We analyzed publicly available aggregated prescription data from the National Database Open Data Japan. Annual outpatient prescription counts for nasal glucagon, injectable glucagon, and insulin formulations were extracted for fiscal years 2014-2023, and their annual trends were then described.

The nasal glucagon prescription increased markedly in fiscal year 2020, the year of market introduction, and remained stable from 2021 to 2023. Contrarily, injectable glucagon prescriptions declined after 2020. Total glucagon-related expenditures, calculated based on the annual drug prices, increased approximately 28-fold between fiscal years 2019 and 2023. Insulin prescriptions increased steadily throughout the study. By age group, long-acting insulin showed increasing use among older patients, whereas rapid- and ultra-rapid-acting insulin showed increasing use among older and younger patients.

Nasal glucagon demonstrated a rapid initial uptake but remained at a stable prescription level thereafter, while substantially increasing the overall glucagon expenditures. Although the drug cost is high, its potential to enable rapid rescue by caregivers is critical. Identifying the appropriate target populations by balancing high drug costs against reduced emergency medical costs to ensure cost-effectiveness will be critical for the effective management of severe hypoglycemia.

The online version contains supplementary material available at 10.1007/s13340-026-00880-y.