Evaluation of the efficacy and safety of olopatadine and fexofenadine compared with placebo in Japanese cedar pollinosis using an environmental exposure unit.
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.


OBJECTIVE
To evaluate the efficacy 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 significant 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.
Enomoto
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Division of Otolaryngology-Head and Neck Surgery, Department of Medicine of Sensory and Motor Organs, Tottori University Faculty of Medicine, Tottori, Japan. t-enomoto@mud.biglobe.ne.jp
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Sakoda
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D000328:Adult; D000485:Allergens / Q000276:immunology*; D032485:Cryptomeria / Q000276:immunology; D003990:Dibenzoxepins / Q000008:administration & dosage / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D039563:Histamine H1 Antagonists, Non-Sedating / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects / Q000276:immunology; D000069605:Olopatadine Hydrochloride; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000188:drug therapy* / Q000276:immunology; D012890:Sleep / Q000187:drug effects; D012912:Sneezing / Q000187:drug effects; D016593:Terfenadine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives; D016896:Treatment Outcome
D000485:Allergens; D003990:Dibenzoxepins; D039563:Histamine H1 Antagonists, Non-Sedating; D000069605:Olopatadine Hydrochloride; D016593:Terfenadine; C093230:fexofenadine