Epinastine Hydrochloride

Objectives: 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. Methods: 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. 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. Conclusions: 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.

Urticaria is induced by the histamine released from mast cells which develops wheals (edema) as a visual feature. In clinical practice, second-generation histamine H₁ -receptor blockers are routinely used as the first-line symptomatic treatment for urticaria. Nevertheless, not much research has directly examined the second-generation histamine H₁-receptor blockers' ability to reduce edema. In this study, we directly evaluated the anti-edematous activities of three second-generation histamine H₁-receptor blockers available in the market (epinastine hydrochloride, cetirizine hydrochloride, and levocetirizine hydrochloride) using a λ-carrageenan-induced footpad edema model. One hour before the induction of edema with 1% λ -carrageenan injection, all second-generation histamine H₁ -receptor blockers (5, 10, 50 and 100 mg/kg) were subcutaneously administered to rats. At 0.5 and 3 hours after λ -carrageenan administration, the edema volume was evaluated using a Plethysmometer. Epinastine hydrochloride significantly suppressed the edema growth in a dose-dependent manner. Cetirizine hydrochloride showed a slight anti-edematous effect, while levocetirizine significantly inhibited the development of edema in a dose-dependent manner. On the other hand, dextrocetirizine did not prevent edema from growing. In summary, second-generation histamine H₁ -receptor blockers, at least those examined in this study, may be able to reduce the clinical symptoms of urticaria associated with edema. Levocetirizine hydrochloride is also anticipated to have stronger anti-edematous effects than cetirizine hydrochloride because levocetirizine is responsible for cetirizine's anti-edematous activity.