Effect of desloratadine versus placebo on nasal airflow and subjective measures of nasal obstruction in subjects with grass pollen-induced allergic rhinitis in an allergen-exposure unit

Abstract

Background: Unlike many antihistamines, desloratadine can reduce nasal congestion in patients with seasonal allergic rhinitis (SAR). Objective: We compared the effects of 5 mg of desloratadine and placebo on nasal airflow and SAR symptoms, including nasal congestion, in response to grass pollen in an allergenexposure unit. Methods: In a randomized, double-blind, placebo-controlled, crossover trial, 47 subjects with histories of SAR received desloratadine or placebo every morning for 7 days and, after a 10-day washout period, were crossed over to the other treatment arm for 7 days. Subjects underwent a 6-hour allergen exposure on day 7 of each treatment period. Nasal airflow and nasal secretion weights were measured before and every 30 minutes during allergen exposure; SAR symptoms (including nasal congestion) were scored before exposure and every 15 minutes thereafter. Results: Nasal obstruction, as measured by nasal airflow, was less severe with desloratadine than with placebo (P