Purpose: To compare the clinical efficacy of Patanol (olopatadine hydrochloride ophthalmic solution 0.1%) to Claritin (loratadine 10 mg) tablets, in the conjunctival allergen challenge model.
Methods: This was a randomized, double-masked, single center, contralateral controlled, antigen challenge model study. The concentration of allergen that elicited a positive response was determined at Visits 1 and 2 (itching > or = 2 and redness > or = 2 OU). At Visit 3, 29 subjects were randomized into two groups. Fifteen subjects received Claritin tablet and Patanol ophthalmic solution 0.1% in one eye and placebo in the contralateral eye. Fourteen subjects received placebo tablet and Patanol in one eye and placebo in the contralateral eye. One hour after drug administration, subjects were challenged with the antigen that elicited a positive response. At 3, 7, and 10 minutes, itching was subjectively evaluated. At Visit 4, the same procedure was followed as in Visit 3, but antigen challenge occurred 8 hours after drug instillation.
Results: Results were analyzed by eye. Eyes treated with Patanol (concomitant with placebo tablet) had significantly lower ocular itching scores when compared to eyes treated with placebo (concomitant with Claritin) at 3, 7 and 10 minutes in the onset of action evaluation (p < 0.05). Eyes treated with Patanol (concomitant with placebo tablet) had significantly lower ocular itching scores at 7 minutes and there was a statistical trend (0.05 < p < 0.1) at 10 minutes in duration of action evaluation.
Conclusions: Patanol therapy was significantly more efficacious than Claritin in reducing ocular itching related to allergic conjunctivitis.