phenylethylidenehydrazine phenylethylidenehydrazine phenylethylidenehydrazine (peh), also known as 2-phenylethylhydrazone or β-phenylethylidenehydrazine, is an inhibitor of the enzyme gaba transaminase (gaba-t). it is a metabolite of the antidepressant phenelzine and is responsible for its elevation of gaba concentrations. peh may contribute to phenelzine's anxiolytic effects. phenylethylidenehydrazineclinical dataatc codenonelegal statuslegal status in general: uncontrolled pharmacokinetic dataelimination half-life~12 hoursidentifiers iupac name (1e)-(2-phenylethylidene)hydrazine cas number29443-41-2 ypubchem cid10103216chemspider8278744unii9fz4w7j6vecomptox dashboard (epa)dtxsid20435557 chemical and physical dataformulac8h10n2molar mass134.182 g·mol−13d model (jsmol)interactive image smiles n/n=c/cc1=cc=cc=c1