In response to particular molecular aggressions, mammalian physiological responses such as IgE-dependent allergies, anaphylactic shocks or inflammation are often associated to concentration excess of histamine. Antihistamine drugs targeting 4 human histamine receptors (HR), have been employed during years to reduce histamine-dependent physiological alterations. However, due to some out-of-target effects, searches for more specific antihistamine drug-like compounds still continue.