Functional prescribing patterns of 111 Kampo formulations in contemporary hospital practice: a 21-year prescription- and patient-level analysis from Japan.

BACKGROUND: Kampo medicine, the traditional Japanese system of herbal medicine, is widely integrated into contemporary medical practice in Japan. However, comprehensive evaluations of long-term prescribing patterns across multiple Kampo formulations remain limited. OBJECTIVES: To characterize utilization patterns of major Kampo medicines in a Japanese tertiary-care hospital using prescription- and patient-level data collected over 21 years. MATERIALS AND METHODS: We conducted a retrospective database study of all Kampo prescriptions issued at a Japanese university hospital between April 2001 and March 2022. Prescription-based analyses examined prescription numbers, total prescription days, and cumulative prescribed amounts. Patient-based analyses evaluated treated patients, age, sex, initial prescribing department, inpatient status at first prescription, and prescription-to-patient ratios. RESULTS: Kampo medicines accounted for 288,815 prescriptions (1.7% of all prescriptions) and were prescribed to 57,634 patients (4.4% of all patients). Daikenchuto ranked first in patient numbers, prescriptions, total prescription days, and cumulative prescribed amounts. Distinct prescribing patterns were observed among formulations, and hierarchical cluster analysis further supported the proposed functional classification. Based on prescription-to-patient ratios, demographics, and clinical settings, major Kampo medicines were classified into four groups: acute symptomatic medicines (Kakkonto, Bakumondoto, and Shoseiryuto), chronic management medicines (Hochuekkito, Rikkunshito, Yokukansan, and Goshajinkigan), inpatient/perioperative medicines (Daikenchuto and Shakuyakukanzoto), and women's health medicines (Tokishakuyakusan and Kamishoyosan). Daikenchuto showed a particularly high rate of inpatient initiation. CONCLUSIONS: Although the study setting was a single tertiary-care university hospital, this real-world analysis identified distinct functional prescribing patterns among major Kampo medicines and provides a comprehensive overview of Kampo utilization in contemporary Japanese hospital practice.