Comparative inhibition by bilastine and cetirizine of histamine-induced wheal and flare responses in humans

Abstract

Comparison of bilastine and cetirizine in inhibiting skin wheal and flare responses over 24h. Twenty-one healthy male volunteers (aged 19-44years). Volunteers were randomised to receive single oral doses of 20 or 50mg bilastine, 10mg cetirizine or placebo before provocation of wheal and flare responses to 100mg/ml histamine by skin prick 1.5, 4, 8, 12 and 24h later. There were no significant differences between overall inhibitions of wheal or flare by 20mg bilastine and 10mg cetirizine. Bilastine was faster in onset than cetirizine, inhibitions of wheal and flare at 1.5h being 89±3 versus 44±14% (P=0.011) and 85±4 versus 45±14% (P=0.016), respectively (Student's t test). At 1.5h, both wheals and flares were inhibited by >70% in 11/12 volunteers taking bilastine and 3/11 taking cetirizine (P=0.003, Fisher's exact test). There were no significant differences between the drugs at later times. Bilastine 50mg had a longer duration of action than bilastine 20mg. Both 20mg bilastine and 10mg cetirizine are effective and of long duration in reducing histamine-induced wheal and flare responses, the major difference between the two drugs being the more rapid onset of action of bilastine.