The Effect of a Combined Therapy with a Histamine H1 Antagonist and a Chemical Mediator Release Inhibitor on Allergic Conjunctivitis

Purpose: To evaluate the efficacy of a combined therapy with levocabastine hydrochloride ophthalmic suspension and pemirolast potassium ophthalmic solution compared to single therapy with levocabastine hydrochloride ophthalmic suspension alone. Methods: Thirty-two allergic conjunctivitis patients were randomized to combined-treatment (n = 15) or single-treatment groups (n = 17). The improvement of subjective symptoms as well as objective findings were evaluated. Results: The degree of improvement was significantly higher in the combined-treatment group for lacrimation (p = 0.008) among the subjective symptoms, for conjunctival edema (p = 0.030), eyelid edema (p = 0.032) and conjunctival papilla formation(p = 0.040) among the objective findings. Conclusions: Both objective assessments and subjective symptoms of allergic conjunctivitis showed the greatest improvements when patients were treated with combined therapy as compared to single-agent therapy. The enhanced benefits of combined therapy may result from these agents having different mechanisms of action.