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Original Article


Evaluation of the Efficacy and Safety of Olopatadine and Fexofenadine Compared With Placebo in Japanese Cedar Pollinosis Using an Environmental Exposure Unit


T Enomoto,1,2 H-Q Lu,3 M Yin,3 T Sakoda,4 Y Dake,5 K Enomoto,6 T Ide,7 L Cheng3

1 Division of Otolaryngology-Head and Neck Surgery, Department of Medicine of Sensory and Motor Organs, Tottori University Faculty of Medicine, Japan
2 NPO Japan Health Promotion Supporting Network, Wakayama, Japan
3 Department of Otorhinolaryngology and International Center for Allergy Research, Nanjing Medical University, The First Affiliated Hospital, Nanjing, China
4 Department of Otolaryngology, Izumisano Municipal Hospital, Rinku General Medical Center, Osaka, Japan
5 Dake ENT and Allergy Clinic, Wakayama, Japan
6 Department of Otolaryngology and Sensory Organ Surgery, Osaka University Medical School, Osaka, Japan
7 Department of Chemistry, Nara Medical University, Nara, Japan

J Investig Allergol Clin Immunol 2009; Vol. 19(4): 299-305



Background: Second-generation oral H1-antihistamines have become a mainstay of treatment for the symptoms of seasonal allergic rhinitis; however, the effect of olopatadine has not been widely reported to date.

Objectives: To evaluate the effi cacy of 2 oral H1-antihistamines, olopatadine and fexofenadine, in the treatment of the nasal symptoms of Japanese cedar pollinosis and their possible side effects.

Methods: This was a randomized, double-blind, placebo-controlled, crossover study conducted in an environmental exposure unit (EEU). Twenty volunteers suffering from Japanese cedar pollinosis were randomly divided into 3 groups and exposed to cedar pollen in the EEU with oral administration of olopatadine hydrochloride (5 mg), fexofenadine hydrochloride (60 mg), or placebo 1 hour prior to pollen exposure.
Nasal symptoms, activity impairment, and subjective sleepiness were self-assessed during the study period. Attention was measured using the digit cancellation test. The trial was repeated after 4 and 7 weeks.

Results: Compared with placebo, olopatadine significantly improved nasal symptoms and activity impairment during pollen exposure (P<.05). There was no significant relief of nasal discharge or nasal congestion with fexofenadine throughout the 5-hour exposure to cedar pollen. Furthermore, olopatadine significantly reduced nasal congestion during the first 2 hours, as well as sneezing and nasal discharge 4 hours after admission to the EEU compared with fexofenadine (P<.05). There was no signifi cant difference in the effect on subjective sleepiness among the 3 groups, and all 3 agents had little effect on attention.

Conclusions: These findings suggest that olopatadine is more effective than placebo and fexofenadine in improving nasal symptoms of Japanese cedar pollinosis.

Key words: H1-antihistamines. Olopatadine. Fexofenadine. Allergic rhinitis. Japanese cedar pollinosis. Environmental exposure unit. Randomized controlled trial.