Safety of Sublingual Immunotherapy: A Secondary Analysis of Post-marketing Adverse Events Reports Using a Japanese Public Database

Purpose Allergic rhinitis impacts a significant portion of the Japanese population, leading to the rise of sublingual immunotherapy (SLIT) as an alternative treatment. Despite its growing popularity, there is limited safety information. Therefore, this study aimed to consolidate data on its adverse effects in an academic context. Methods We conducted a secondary analysis of adverse events reported in the Pharmaceutical Adverse Events Information Database for three SLIT drugs (Actair®, Cedarcure®, and Miticure®) approved in Japan. A descriptive analysis concerning age, gender, underlying diseases, symptoms, time of onset, and outcomes was performed. Results We identified 98 cases of adverse reactions reported for the SLIT drugs. These cases were mainly from the pediatric to adolescent group (73.7%). Males made up 59.5% of reports. Recovery or improvement was noted in 97.7% of reports. Anaphylactic reactions were the most common adverse event (42.6%), followed by respiratory distress (12.2%). Reactions typically occurred within one week of starting treatment (54.1%). Conclusions Our research illuminated the safety of SLIT drugs in Japan, revealing a favorable profile. It underscores the need for vigilance, particularly among younger patients and during initial doses, emphasizing the importance of proper patient selection and further research to enhance the treatment's efficacy.