Irdabisant (CEP-26401) (CEP-26401) is a selective, orally active and blood-brain barrier (BBB) penetrant antagonist/inverse agonist of histamine H3 receptor (H3R) (rat H3R Ki= 7.2 nM, human H3R Ki= 2.0 nM). Irdabisant exhibits relatively low inhibitory activity against hERG current (IC50= 13.8 μM). Irdabisant exhibits cognition-enhancing and wake-promoting activities in the rat social recognition model. Irdabisant can be used for research on schizophrenia or cognitive impairment.