Comparison of effects of topical levocabastine and nedocromil sodium on the early response in a conjunctival provocation test with allergen.

Abstract

Multiple ocular challenges or seasonal trials have demonstrated the efficacy of levocabastine and nedocromil sodium in the treatment of allergic conjunctivitis. This study was designed to compare the protective effect of levocabastine eye drops with that of nedocromil in a conjunctival provocation test with allergen. Twenty-four patients with allergic conjunctivitis to grass pollen were recruited. After a preliminary provocation to determine conjunctival reaction threshold (erythema of at least 50% of the conjunctiva with ocular itching), patients were randomized to receive either topical levocabastine (0.05%) or nedocromil (2%) 15 minutes before provocation. Erythema and pruritus intensity were recorded at each concentration of allergen up to the reaction threshold. The allergen concentration level necessary to reach reaction threshold was increased (p < 0.001) after treatment with both drugs. Comparison between screening and each treatment indicated that the shift in allergen concentration was significantly greater after levocabastine treatment than after nedocromil treatment (p = 0.019). Conjunctival itching (symptom score) and erythema (percent conjunctival surface) were also better controlled by levocabastine than by nedocromil during provocation (p < 0.05). In a provocation test with allergen, levocabastine and nedocromil were both effective in increasing the conjunctival tolerance to allergen, with better protection provided by levocabastine.