Cipralisant (GT-2331) is an orally active, low-toxicity, potent, selective, high affinity histamine H3 receptor full antagonist in vivo, and an agonist in vitro, with a pK i of 9.9 for histamine H3 receptor and a K i of 0.47 nM for rat histamine H3 receptor . Cipralisant has the potential for attention-deficit hyperactivity disorder research . Cipralisant is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.