A randomized, placebo-controlled trial revealed that intranasal Levocabastine + Mometasone furoate nasal spray (MFNS) was well-tolerated and significantly improved total nasal symptom score (TNSS) when compared to MFNS + placebo in Japanese cedar pollinosis (JCP) patients. The primary goal of this study was to determine the safety and effectiveness of antihistamine and corticosteroid combination for management of JCP, the most prevalent seasonal allergic rhinitis.

Overall, 20 patients per group received either Levocabastine nasal spray plus MFNS (Levocabastine group) or placebo nasal spray plus MFNS (placebo group). Inter-group differences in TNSS following treatment was the major outcome ascertained. The secondary endpoints were differences in total symptom score, total ocular symptom score, total symptom-medication scores, total medication score, and five individual symptoms along with safety.

Compared to the placebo group, alteration in total TNSS was higher in Levocabastine group. In the Levocabastine group, a substantial decline in TNSS was witnessed more than 6 days sooner when compared to the placebo group. Secondary endpoints showed similar add-on effects. Both therapies were tolerated satisfactorily.

When combined with intranasal corticosteroid therapy, treatment with intranasal antihistamine not only controlled the nasal symptoms, but also the ocular symptoms, and reduced the requirement for rescue drugs in JCP patients.