Lack of Clinical Relevance of Bilastine-Food Interaction in Healthy Volunteers: A Wheal and Flare Study

Introduction: The aim of this study was to compare the pharmacodynamic activity of bilastine administered under fasting and fed conditions in healthy volunteers.

Methods: In this randomized, open-label, two-period, crossover study involving 24 healthy subjects, once-daily oral bilastine 20 mg was administered for 4 days under fasting and fed conditions, with a 7-day washout period. Bilastine plasma concentrations were measured for 24 h after the first and fourth doses in each period. Pharmacodynamic activity was assessed by wheal and flare surface inhibition and subjective assessment of itching, after intradermal injection of histamine 5 μg.

Results: When administered under fed versus fasting conditions, exposure to bilastine 20 mg decreased (mean maximum plasma concentration and area under the curve from time 0 to 24 h decreased by 34.27% and 32.72% [day 1], respectively, and 33.08% and 28.87% [day 4]). Despite this, the antihistaminic effect of bilastine 20 mg was not altered by food. On day 1, as assessed by wheal and flare surface inhibition, the maximum effect and duration of action of bilastine did not differ to a significant extent between fasting and fed conditions, with only a short 30-min delay in the onset of wheal inhibition. At steady state (day 4), bilastine's pharmacodynamic effects were not significantly affected under fasting or fed conditions.

Conclusion: The pharmacokinetic interaction of bilastine with food does not imply a significant reduction of its peripheral antihistaminic efficacy. Despite a slight delay in onset of action on the first treatment day, the global clinical efficacy of bilastine is not affected by coadministration with food.