Cimetidine for Pediatric Use in Japan: Rising Prescriptions for a New Indication.

Cimetidine is effective for treating periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) syndrome, primarily in children, and is covered by public insurance in Japan. However, as demand for gastric ulcer treatment declines, cimetidine production has been restricted, raising concerns about supply for pediatric patients. We analyzed Japanese prescription trends in adults and children using publicly available data. Specifically, national reimbursement data were used to assess annual cimetidine prescription volumes by age group and pediatric share. Chronological changes were examined based on original formulation supply. In the database, 11 and 6 cimetidine products (including discontinued stock) were available for outpatient and in-hospital dispensing, respectively. Annually, 1.01 million and 80,000 cimetidine tablets (200-mg equivalents) were dispensed for patients under 15 years in outpatient and in-hospital settings, respectively. No inpatient prescriptions were recorded. Pediatric prescriptions peaked at ages 5-9 years, differing from adult trends, and accounted for 2.5% of total prescriptions. Although overall dispensing volumes are declining, pediatric prescriptions are increasing. Despite overall demand decreasing, approximately 1 million 200-mg cimetidine tablets are needed annually for use in children, and pediatric demand is increasing. Therefore, securing production of this new indication is essential.