It belongs to the piperidine class of antihistamines as do loratadine, desloratadine, and fexofenadine (Figure 1).
Like other antihistamines bilastine is an H1 receptor inverse agonist.
In vivo studies in rats have demonstrated reduction in histamine-stimulated smooth muscular contraction, bronchospasms, endothelial permeability, and microvascular extravasation .
In vivo studies in the human population have demonstrated an inhibition of histamine-induced wheal and flare response activity of the skin which was marked with bilastine 20 mg as with cetirizine 10 mg .
Though they are helpful in many patients with mild disease, the available non-sedating antihistamines may not be sufficiently efficacious in moderate to severe conditions [1, 2].
Several mediators are involved in the pathophysiology; however, histamine plays a vital role in the allergic immediate reaction .The observations indicate that non-sedating antihistamines, as opposed to what has been thought previously, may be helpful in patients with allergic rhinitis in whom nasal obstruction is a major concern.Current international guidelines need to be revised in the light of the recent evidence.Research into aspects of pharmacokinetics and efficacy and adverse effect profiles of bilastine in children under 12 years of age is needed as are dose-response assessments and studies planned rigorously with the aim of assessing quality of life effects.Current guidelines for diagnosis and treatment of allergic rhinoconjunctivitis and urticaria recommend nonsedating antihistamines as first line treatment [1, 2].In the fasting state bilastine is quickly absorbed, but the absorption is slowed when it is taken with food or fruit juice.Therefore, it is recommended that bilastine is taken at least one hour before and no sooner than two hours after a meal.A Pub Med literature search from January 1, 2000, through April 1, 2013, was conducted to track down randomized controlled studies of clinical efficacy of bilastine.This was supplemented with additional papers on bilastine and abstracts cited in reference lists, obtained from online sources, or supplied by Berlin-Chemie A. The literature search revealed 2 efficacy studies in allergic rhinoconjunctivitis [14, 15], 1 in perennial rhinitis , and 1 in chronic idiopathic urticaria .In healthy adults, a mean oral systemic availability of bilastine of 61% has been reported .The reduction seems to be due to a downregulation of the cell transport activity in the intestinal mucosa, the so-called organic anion-transporting polypeptides (OATP1A2) .