tritoqualine tritoqualine tritoqualine, also known as hypostamine, is an inhibitor of the enzyme histidine decarboxylase and therefore an atypical antihistamine, used for the treatment of urticaria and allergic rhinitis with no known adverse effects. tritoqualineclinical dataahfs/drugs.cominternational drug namesatc coder06ax21 (who) identifiers iupac name 7-amino-4,5,6-triethoxy-3-(4-methoxy-6-methyl-7,8-dihydro-5h-dioxoloisoquinolin-5-yl)-3h-isobenzofuran-1-one cas number14504-73-5pubchem cid72145chemspider65119uniif4mw5166yhchemical and physical dataformulac26h32n2o8molar mass500.548 g·mol−13d model (jsmol)interactive image smiles ccoc1=c(c(=c(c2=c1c(oc2=o)c3c4=c(c5=c(c=c4ccn3c)oco5)oc)n)occ)occ