Efficacy of once-daily olopatadine 0.2% ophthalmic solution compared to twice-daily olopatadine 0.1% ophthalmic solution for the treatment of ocular itching induced by conjunctival allergen challenge.

Olopatadine 0.1% (Patanol) and olopatadine 0.2% (Pataday) ophthalmic solutions are topical ocular anti-allergic agents with antihistaminic and mast cell stabilizing properties. The efficacy of two doses of olopatadine 0.1% was compared to one dose of olopatadine 0.2% in the prevention of ocular itching associated with allergic conjunctivitis over 24 hours. This double-masked conjunctival allergen challenge (CAC) study found no significant difference in the mean itching scores between two drops of olopatadine 0.1% and one drop of olopatadine 0.2%. Both showed significant activity at the 24-hour time point and were statistically superior to placebo. No adverse events occurred while on drug therapy.