Study shows medication benefits in cat allergy sufferers

Boston-Epinastine HCl 0.05% ophthalmic solution (Elestat, Inspire/Allergan) safely and effectively relieves the signs and symptoms of allergic conjunctivitis due to cat dander, according to the results of a clinical trial conducted by researchers from New England Eye Center, Tufts University, Boston.

The single-center study had a randomized, single-dose, paired-eye, double-masked design that compared epinastine with olopatadine HCl 0.1% ophthalmic solution (Patanol, Alcon Laboratories). A total of 30 qualified healthy subjects with a history of ocular allergies to cats were evaluated in a cat exposure room having allergen levels comparable to those found in cat-containing homes.

Baseline evaluations of ocular itching, burning, tearing, conjunctival hyperemia, chemosis, nasal itching, and rhinorrhea were obtained 30 minutes after entry into the room. A single drop of epinastine ophthalmic solution was then placed in one eye and olopatadine ophthalmic solution was instilled contralaterally. These signs and symptoms were re-evaluated 5, 15, 30, 45, and 60 minutes after drop installation.

The study showed that both anti-allergy medications were effective in quickly reducing these allergic signs and symptoms. No adverse events were reported.

"Epinastine is a potent multimodal antihistamine that has both mast-cell-stabilizing activity and anti-inflammatory properties. It has been shown to be effective, safe, and well tolerated for the treatment of allergic conjunctivitis using the conjunctival allergen challenge model as well as in environmental studies. The results of our study, combined with those of previous investigations, support the conclusion that both epinastine and olopatadine provide rapid relief of the signs and symptoms of allergy," said Bryan Monson, BS, research associate, New England Eye Center, Boston.

"It is important to note that clinically significant difference between the drugs is likely minimal. Additionally, the small sample size of this study would require further investigation to draw strong clinical conclusions regarding a comparison between epinastine and olopatadine," said Jason Rothman, MD, cornea fellow, New England Eye Center, Tufts University, Boston.

Subjects were eligible for inclusion if they were at least 18 years old, had a history of ocular allergy to cats, and developed ocular itching with a severity score of 2 (mild itch, without desire to rub eyes) when placed in the cat exposure room. All study participants wore TB masks during allergen exposure and underwent pulmonary function testing periodically while in the cat exposure room. Subjects with a history of asthma were excluded from the study.

The results from the evaluations showed a greater reduction in ocular itching for epinastine at most time points. In addition, there were statistically significant differences in reduction of symptoms of nasal itching and hyperemia favoring olopatadine. In analyses of scores for ocular burning, tearing, nasal itching, and runny nose, there were no differences between the two drugs.