Oral Tetracycline Use in Children and Adolescents in Japan: Trends, Indications, and Treatment Patterns.

Antimicrobial use among children in Japan has declined substantially; however, tetracycline use has increased among adolescents, particularly after 2017 and during the COVID-19 period, and the underlying clinical indications remain unclear. We aimed to characterize long-term trends in oral tetracycline use, changes in clinical indications, and treatment patterns among individuals aged < 20 years in Japan. We conducted a time-series analysis using a nationwide administrative claims database of Japan Health Insurance Association from 2015 to 2023, including 24 million individuals aged < 20 years. Oral tetracycline use was measured as days of therapy (DOTs) per 1000 inhabitants per day, and clinical indications were identified using ICD-10 codes. We assessed trends in tetracycline use and indications over time and described treatment patterns, including concomitant therapies, among patients with acne vulgaris. Oral tetracycline use increased from 0.95 to 1.76 DOTs per 1000 inhabitants per day between 2015 and 2023, primarily driven by doxycycline, with a marked rise after 2020 and highest use among adolescents. The clinical indications shifted substantially, with the proportion of acne vulgaris increasing from 34.1% to 73.6% while respiratory infections decreased, and the mean treatment duration for acne was 37.9 days. Among patients with acne, concomitant use of adapalene- and benzoyl peroxide-based therapies was limited, whereas topical antibiotics were commonly used. Oral tetracycline use among individuals aged < 20 years in Japan increased substantially, with a marked shift in clinical indications toward acne vulgaris. These findings provide a basis for further evaluation of acne treatment patterns, including the use of oral tetracyclines and non-antibiotic topical therapies, in Japan.