propanidid propanidid propanidid is an ultra short-acting phenylacetate general anesthetic. it was originally introduced by bayer in 1963 but anaphylactic reactions caused it to be withdrawn shortly afterwards. propanididclinical datatrade namesepontolahfs/drugs.cominternational drug namesatc coden01ax04 (who) identifiers iupac name propyl acetate cas number1421-14-3 ypubchem cid15004drugbankdb13234 nchemspider14283 yuniiao82l471nskeggd05626 ychebichebi:135432chemblchembl2105345comptox dashboard (epa)dtxsid7048825 echa infocard100.014.384 chemical and physical dataformulac18h27no5molar mass337.416 g·mol−13d model (jsmol)interactive image smiles o=c(occc)cc1cc(oc)c(occ(=o)n(cc)cc)cc1 inchi inchi=1s/c18h27no5/c1-5-10-23-18(21)12-14-8-9-15(16(11-14)22-4)24-13-17(20)19(6-2)7-3/h8-9,11h,5-7,10,12-13h2,1-4h3 ykey:kejxlqupyhwcnm-uhfffaoysa-n y ny (what is this?) (verify) even though cremophor el has been shown to cause anaphylactic reactions in humans in several cases (both when given intravenously and orally), it is still debated whether propanidid itself may have contributed to the reactions. it has been argued that the toxic effects or reactions to propanidid (and althesin) were due to the drugs themselves. several cases of negative reactions have been recorded for different drugs using cremophor el as solubilizer, suggesting that the negative reactions were mainly caused by cremophor and not by the drug substances themselves.