epinastine epinastine epinastine (brand names alesion, elestat, purivist, relestat) is a second-generation antihistamine and mast cell stabilizer that is used in eye drops to treat allergic conjunctivitis. it is produced by allergan and marketed by inspire in the united states. it is highly selective for the h1 receptor and does not cross the blood-brain-barrier. epinastineclinical datatrade namesalesion, elestat, purivist, relestatahfs/drugs.commonographmedlineplusa604011pregnancycategory c routes ofadministrationeye dropsatc coder06ax24 (who) s01gx10 (who)pharmacokinetic dataprotein binding64%elimination half-life12 hoursidentifiers iupac name (rs)-3-amino-9,13b-dihydro-1h-dibenz(c,f)imidazo(1,5-a)azepine cas number80012-43-7 ypubchem cid3241iuphar/bps7176drugbankdb00751 ychemspider3128 yuniiq13wx941efkeggd07900 ychebichebi:51032 ychemblchembl1106 ycomptox dashboard (epa)dtxsid2048371 echa infocard100.120.187 chemical and physical dataformulac16h15n3molar mass249.317 g·mol−13d model (jsmol)interactive image smiles n\4=c(\n3c1c(cccc1)cc2c(cccc2)c3c/4)n inchi inchi=1s/c16h15n3/c17-16-18-10-15-13-7-3-1-5-11(13)9-12-6-2-4-8-14(12)19(15)16/h1-8,15h,9-10h2,(h2,17,18) ykey:whwzlsfabnneni-uhfffaoysa-n y (verify) it was patented in 1980 and came into medical use in 1994.