Efficacy of fexofenadine versus desloratadine in suppressing histamine-induced wheal and flare.

To date, no published articles exist comparing the H1-receptor antagonist activities of fexofenadine and desloratadine using the histamine-induced skin wheal-and-flare model. The aim of this study was to compare the efficacy of fexofenadine versus desloratadine in suppressing histamine-induced skin flares and wheals in adults and adolescents. This was a two-center, randomized, placebo-controlled, complete-crossover study. Subjects were administered either single-dose fexofenadine HCl, 180 mg; desloratadine, 5 mg; or placebo and their response to skin-prick testing with histamine and diluent was recorded at predetermined time intervals. The primary end point was change in size of histamine-induced summation skin flares. Secondary end points included change in skin wheal summation measurements, onset, duration, maximum percent suppression, and time to maximum suppression of flares and wheals. Fexofenadine suppressed skin flares significantly more than desloratadine from 2 to 6 hours, and wheals from 2 to 4 hours, 6 to 9 hours, and 12 hours posttreatment. In addition, fexofenadine suppressed flares more than placebo at all time points from 2 to 24 hours and wheals more than placebo at all time points from 2 to 12 hours posttreatment. Desloratadine suppressed flares significantly more than placebo from 6 to 10 hours and at 12 and 24 hours but suppressed wheals significantly versus placebo only at 10 hours. Fexofenadine had a faster onset of flare suppression than desloratadine (1 hour versus 5 hours) and an equally rapid onset of wheal suppression. Fexofenadine HCl, 180 mg, was superior to desloratadine, 5 mg, in histamine-induced wheal-and-flare suppression, suggesting increased in vivo H1-receptor antagonist potency of fexofenadine versus desloratadine.