H1 antihistamines work as inverse agonists that drive the balance toward the inactive side and suppress the effects of histamine.
Since these effects are not genuine antagonistic but rather represent a balance displacement between active and inactive forms of H1 receptors, now, the term H1 antihistamine rather than the former “antihistamine antagonist” is used .
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.
There is little evidence, if any, that pharmacokinetic differences between specific drugs are important in clinical use.The biological effects of histamine in the allergic reaction are mediated through H1 receptors that coexist in active and inactive forms of g-protein-coupled receptors which balance each other.Histamine works as an agonist that pushes the balance to the active side leading to effects such as muscular contraction, bronchospasms, upregulation of endothelial permeability, and stimulation of sensory nerves and cough receptors .Non-sedating antihistamines are part of a quite heterogeneous pharmacological group.Bilastine has not been derived structurally from other antihistamines.