Clinical Efficacy of Prophylactic Administration of a Second-Generation Antihistamine to Patients with Japanese Cedar Pollinosis

a Three-year, Multicenter, Retrospective Study

Abstract

Japanese cedar pollinosis (JCP) is a relatively common disease in Japan and is a serious problem between February and April each year. H1 antagonists (antihistamines, including second-generation antihistamines) are used as first-line treatment in most patients. It has recently been recommended that patients who develop severe symptoms of pollinosis every year begin treatment immediately after the start of pollen release or the onset of symptoms. A physician should choose the drug regimen for each patient by selecting from among many second-generation antihistamines according to the amount of pollen release expected during the season and the type and severity of symptoms usually experienced by the patient during the peak season. However, there is wide variation in pollen release among the regions of Japan and from year to year. If constant effectiveness of an antihistamine for patients with JCP were demonstrated by a large-scale multicenter study for several years, it would please both patients with JPC and their physicians.
In this study we investigated the efficacy of the second-generation anti-histamine olopatadine in 1611 patients with JCP attending the clinics of 83 hospitals, for 3 consecutive years. Prophylactic olopatadine was effective against JCP, especially in the season pollen level was low (under 2000/season). In the season when there was a high pollen level, prophylactic olopatadine was effective until the peak pollen release. After one day of therapy olopatadine also significantly improved the nasal symptom scores of patients with moderate to severe symptoms of JCP. These results suggest that olopatadine is a very effective drug for the treatment of JCP.