A study comparing the inhibitory effects of single and repeated oral doses of ebastine and fexofenadine against histamine-induced skin reactivity.

Objective: The aim of this double-blind, randomized, crossover, placebo-controlled clinical trial was to compare the inhibition of the histamine-induced skin reaction induced by ebastine 20 mg with respect to that induced by fexofenadine 120 mg or placebo.

Methods: Eighteen volunteers (10 males, 8 females) received the three treatments once daily for 5 days, with a mean 7-day washout period between treatments. Intradermal tests, using 0.05 ml from a solution containing 100 microg/ml of histamine, were performed at baseline and at 1, 1.5, 2, 3, 10 and 24 h after a single dose and repeated 5-day dose, and in addition after 34, 48, 58 and 72 h after repeated 5-day dose.

Results: After 24 h of acute administration, ebastine 20 mg was significantly more effective than fexofenadine 120 mg in reducing the wheal and flare induced by histamine challenge (p<0.001). Although fexofenadine 120 mg had the shortest onset of action (1.5 vs. 3 h in ebastine 20 mg), the duration of its antihistamine effect was the shortest (24 vs. 58 h in ebastine 20 mg) and wheal reduction after 24 h was not significantly different from placebo. The overall effect after single and repeated 5-day dose, expressed as the AUC of reduction of wheal and flare area (%/h), showed the following order of magnitude: ebastine 20 mg>fexofenadine 120 mg>placebo. No significant differences in the incidence of adverse events were found between the three treatments.

Conclusions: The present results clearly show a superior and long-acting effect of ebastine 20 mg compared with fexofenadine 120 mg on the skin response to histamine 24 h after dosing.