The added benefit of local patanol therapy when combined with systemic Claritin for the inhibition of ocular itching in the conjunctival antigen challenge model

Background: Allergic conjunctivitis very often occurs simultaneously with r hinitis in seasonal allergy sufferers. While systemic anti-allergic and ant ihistaminic agents are effective against many signs and symptoms of allergy , they may not adequately control ocular signs and symptoms in patients wit h multiple target organ hypersensitivity. Patanol(R) (olopatadine hydrochlo ride 0.1% ophthalmic solution, Alcon Laboratories, Inc., Fort Worth, TX), a new effective anti-allergic mast cell stabilizer with antihistaminic prope rties, is approved for the prevention of ocular itching due to allergic con junctivitis. Objective: To determine whether Patanol in combination with th e systemic antihistamine Claritin(R) (loratadine, Schering, Kenilworth, NJ) reduces the ocular itching associated with allergic conjunctivitis more ef fectively than Claritin alone. A topical ocular antigen challenge induced t he allergic conjunctivitis in 15 subjects. Methods: This was a randomized, double-masked study in which the contralateral eye served as the control. O n Visit 1, an allergen dose which elicited response scores >2 for ocular it ching was identified. Itching was graded by the subject using a 0 to 4 poin t scale. At Visit 2, the threshold allergen concentration was confirmed. At Visit 3, the onset of action challenge, in addition to Claritin (10 mg tab let), each subject received Patanol in one eye and placebo in the fellow ey e in a randomized, double-masked fashion. Allergen was instilled one hour a fter dosing, and ocular itching was graded at 3, 7, 10 and 20 minutes after challenge. At Visit 4, the duration of action challenge, the same drug reg imen was followed as in Visit 3. However, allergen challenge was performed eight hours after dosing, and itching graded after 3, 7, 10 and 20 minutes. Results: Patient eyes treated with Patanol were significantly less itchy t han those treated with systemic Claritin alone at critical time points 3, 7 , and 10 minutes after the onset of action challenge (p<0.05), and at 3 and 7 minutes after the duration of action challenge (p<0.05). Conclusion: The addition of topical Patanol to systemic Claritin therapy significantly red uced ocular itching associated with allergic conjunctivitis compared to tre atment with Claritin alone. These findings prove the added benefit of local Patanol therapy in the treatment of ocular allergic symptoms in patients r eceiving systemic antihistamines for concomitant systemic allergies.