Histamine antagonist Bepotastine suppresses nasal symptoms caused by Japanese cedar and cypress pollen exposure.

Objective: To determine the efficacy of the antihistamine bepotastine on treating nasal symptoms in patients with Japanese cedar and cypress pollinosis, based on two previous studies that looked at bepotastine OD's inhibitory effect on symptom onset after exposure. Design and methods: Randomized double-blind placebo controlled, parallel study. Twenty-eight volunteers with Japanese cedar and cypress pollinosis were randomly assigned into two experimental groups: a bepotastine-treated or a placebo control group. Subjects received either 10 mg bepotastine tablets or placebo tablets 1 day before entering an artificial exposure pollen chamber (OHIO Chamber) and also for three or more consecutive days. They were exposed to Japanese cedar and cypress pollen for 3 h per day for 2 days. Nasal and ocular symptoms were self-rated by each patient at regular intervals in addition to being objectively measured. Possible cognitive impairment was assessed by using the digit cancellation test (D-CAT). Results: In Study 1, under controlled conditions, there were no significant differences (p > .05) between subjects exposed to Japanese cedar pollen and those exposed to cypress pollen in terms of total nasal symptom score (TNSS). In Study 2, in the placebo group, the amount of nasal discharge and the number of sneezes did not diminish before cypress pollen exposure on the second day (p < .05). This suggests that an antihistamine can suppress the symptoms of hang over. No deterioration of work performance was observed in the bepotastine group after pollen exposure for 2 days, as measured by D-CAT (p > .05). Conclusion: We conclude that bepotastine can suppress allergy-related symptoms without impairing work performance in subjects with seasonal allergic rhinitis caused by Japanese cedar pollen or cypress pollen.