Efficacy of desloratadine in the treatment of allergic rhinitis: a meta-analysis of randomized, double-blind, controlled trials.

The objective of the study is to assess the efficacy of the nonsedating antihistamine, desloratadine, in the treatment of allergic rhinitis (AR). A search of MEDLINE, EMBASE, LILACS, and CINAHL databases was undertaken from January, 1966 to May, 2006. Double-blind, randomized, controlled studies of desloratadine in the treatment of AR in adult patients were carried out. The measured outcomes included the total symptoms score, the total nasal symptoms score, nasal airflow, and inflammatory markers (nasal eosinophils, nasal interleukin-4). The analysis included the calculation of standardized mean difference (SMD). A total of 57 studies were analyzed, and 13 randomized, double-blind, controlled trials were included in the meta-analysis. The trials included 3108 subjects who had completed studies involving desloratadine. There was significant heterogeneity among the study results, because of differing study methodologies. Desloratadine was associated with significant reductions in total symptoms scores (SMD -1.63; 95% CI -2.75 to -0.51; P = 0.004) and total nasal symptoms score (SMD -0.66; 95% CI -0.91 to -0.42; P < 0.001), when compared with placebo. Analysis of objective data on nasal blockage demonstrated a significant improvement in nasal airflow with desloratadine, when compared with placebo (SMD 0.32; 95% CI 0.10 to 0.55; P = 0.005). A benefit favoring desloratadine over placebo in terms of nasal eosinophil levels was also noted in the analysis. This meta-analysis confirms the reduction of AR symptoms and improvement in nasal airflow seen in individual studies of desloratadine. Objective improvements in nasal airflow, total symptoms, and total nasal symptoms seen with desloratadine are supported by Ia evidence.