Efficacy of ebastine, cetirizine, and loratadine in histamine cutaneous challenges

Few studies have compared the antihistaminic effect of ebastine at 20 mg/day (maximal recommended daily dose) with the effect found for other antihistamines in human pharmacologic models.

To compare the inhibition of the histamine-induced skin reaction produced by ebastine (20 mg/day) with that produced by cetirizine (10 mg/day), loratadine (10 mg/day), or placebo in a double-blind, randomized, crossover, placebo-controlled clinical trial.

Twenty volunteers (10 men and 10 women) received the four treatments once daily for 7 days, with a mean 7-day washout period between treatments. Three intradermal histamine challenges (0.05 mL of a 100 microg/mL histamine solution at 4, 8, and 24 hours after drug administration) were performed at baseline, day 1 (single dose), and day 7 (multiple doses). Wheal and flare areas were measured after 15 minutes.

All treatments yielded significant reductions of histamine-induced wheal in comparison to placebo (P < 0.001). Analysis of covariance revealed significant differences between treatments (P < 0.05). Ebastine had a significantly greater antihistaminic effect than did cetirizine or loratadine, except at 4 hours after a single dose versus cetirizine. Further, the effect of cetirizine was similar with single or multiple doses after both 4 and 24 hours, whereas the effect of ebastine showed significant increases in wheal reduction with multiple doses (P < 0.05). No serious adverse events or withdrawals occurred during the study.

This study shows that ebastine in a 20-mg dose is an effective once-daily antihistamine. Superior efficacy was found in comparison to cetirizine (10 mg) or loratadine (10 mg) on the overall skin wheal response after single and multiple doses.