Icatibant promotes patients' behavior modification associated with emergency room visits during an acute attack of...

Hereditary angioedema due to C1-inhibitor (C1-INH) deficiency (HAE-C1-INH) induces an acute attack of angioedema. In 2018, icatibant available for self-possession and subcutaneous self-administration was licensed for on-demand treatment in addition to intravenous C1-INH administration in Japan. We retrospectively evaluated the percentage of attacks in critical parts at emergency room (ER) visits and the time until visiting ER for C1-INH administration before and after the initial prescription of icatibant. The percentage of attacks in critical parts at ER visits before the prescription was 69.2%, but that was 80.0% when patients visited ER for additional C1-INH administration after the self-administration of icatibant. The time from the onset of an acute attack to visiting ER for the additional treatment after the self-administration of icatibant significantly increased from 6.2 h to 19.2 h (p < 0.001). Icatibant, therefore, promoted the patients' behavior modification associated with ER visits for C1-INH administration during an acute attack of HAE-C1-INH.