fenethazine fenethazine fenethazine (inn) (brand names anergen, contralergial, ethysine, etisine, lisergan, lysergan; former developmental code names rp-3015, sc-1627, wy-1143), or phenethazine, is a first-generation antihistamine of the phenothiazine group. promethazine, and subsequently chlorpromazine, were derived from fenethazine. fenethazine, in turn, was derived from phenbenzamine. fenethazineclinical dataother namesphenethazinum, phenethazine, phenetazine; rp-3015, sc-1627, wy-1143identifiers iupac name n,n-dimethyl-2-phenothiazin-10-ylethanamine cas number522-24-7 ypubchem cid68223chemspider61526 yunii8j97cuz4hxkeggd02602chemblchembl2106299 ycomptox dashboard (epa)dtxsid30200233 echa infocard100.007.570 chemical and physical dataformulac16h18n2smolar mass270.39 g·mol−13d model (jsmol)interactive image smiles cn(c)ccn1c2=cc=cc=c2sc3=cc=cc=c31 inchi inchi=1s/c16h18n2s/c1-17(2)11-12-18-13-7-3-5-9-15(13)19-16-10-6-4-8-14(16)18/h3-10h,11-12h2,1-2h3 ykey:pfaxacnygzvkmx-uhfffaoysa-n y