Cost-effectiveness Analysis of Second-Generation Antihistamine 1 Receptor Blockers and Japanese Kampo Shoseiryuto for Treating Perennial Allergic Rhinitis in Outpatient Settings in Japan.

Perennial allergic rhinitis (PAR) is common in Japan. Second-generation antihistamines (SGAs) are commonly used for its treatment; however, it remains unclear which SGA is the most cost-effective. Additionally, the pharmacoeconomics of Japanese Kampo shoseiryuto (which was traditionally prescribed to treat PAR in Japan) remains poorly understood. In this study, we aimed to investigate the effectiveness of various SGAs and shoseiryuto for the treatment of PAR in Japanese outpatients, from the healthcare payer's perspective. The most cost- and clinically effective SGAs were determined from a list of 6 SGAs (bepotastine, 10 mg; cetirizine, 10 mg; ebastine, 10 mg; epinastine, 20 mg; loratadine, 10 mg; and olopatadine, 5 mg) together with shoseiryuto, using the overall improvement rate through a model-based analysis. The time horizon was 28 days. Costs were determined based on the Medical Fee Index in 2020. Deterministic and probabilistic sensitivity analyses were conducted to address the uncertainty of the base-case results. Overall, bepotastine (10 mg) and ebastine (10 mg) were cost-effective. Shoseiryuto was less cost-effective than ebastine (10 mg) (dominated). Ebastine (10 mg) was the most cost-effective option based on deterministic and probabilistic sensitivity analyses. Ebastine (10 mg) was the most cost-effective treatment strategy for PAR among the agents evaluated in this study. This insight could aid in establishing an appropriate formulary for treating PAR in hospitals and communities.