Twenty-four-hour activity and consistency of activity of levocetirizine and desloratadine in the skin.

摘要

AIM: Levocetirizine, the active enantiomer of cetirizine, and desloratadine, the active metabolite of loratadine, are two recently introduced anti-H1 agents. We set out to compare their antihistaminic activity in the skin for 24 h in a double-blind, randomized cross-over trial. METHODS: The skin reaction to histamine administered by prick tests (100 mg ml(-1)) was measured by the surface areas of weals and flares for 24 h [before treatment, 0.5, 1, 2, 3, 4, 6, 8, 10, 12 and 24 h after a single dose of levocetirizine (5 mg), desloratadine (5 mg) or placebo] in 18 healthy volunteers (34.8 +/- 9.4 years; 14 women). The areas under the curves (AUC) of the weal and flare areas as a function of time were compared by ANOVA. RESULTS: A highly significant overall treatment effect (P < 0.0001) was observed and both weals and flares were inhibited. The pairwise comparisons showed that the activity of levocetirizine and desloratadine was significantly superior to that of placebo (P < 0.0001), and the activity of levocetirizine was significantly superior to that of desloratadine (P < 0.0001). 'Total' weal inhibition (> or = 95%) occurred only with levocetirizine. Median values of maximal weal inhibition were 44.2% with placebo, 55.0% with desloratadine and 100% with levocetirizine. The time to maximal weal inhibition was 4 h (median value) for all three study drugs, but scattered over a wider range for desloratadine (3-24 h) than levocetirizine (2-4 h). With desloratadine, five of 18 (28%) subjects reached weal inhibition of at least 70% at between 3 and 10 h, whereas with levocetirizine all subjects [18/18 (100%)] reached this level of weal inhibition at between 1 and 3 h. The median duration of 70% weal inhibition was zero with placebo and desloratadine, and was 21.4 h with levocetirizine (P < 0.0001 between the three study drugs, and P < 0.0001 between the two active drugs). No uncommon adverse events were reported, and no subject withdrew from the study due to an adverse event. CONCLUSION: This study shows that the activity of levocetirizine in suppressing skin reactivity to histamine was clearly superior to that of desloratadine for 24 h after a single dose. In addition, its activity was more consistent and lasted longer.