A Clinical and Biochemical Study of Monoamine Oxidase Inhibition in Depressed Patients

The discovery that iproniazid benefits certain subjects with depression, linked with the demonstration that it inhibits the enzyme monoamine oxidase (MAO), led to the hypothesis that inhibition of MAO was the essential mechanism by which iproniazid caused relief of symptoms (Pletscher, 1959). Iproniazid, unfortunately, can produce serious toxic effects, particularly on the liver (Pare and Sandler, 1959), and this has limited its clinical application. For this reason a search has been made for MAO inhibitors with an effective anti-depressant action yet without the serious toxic effects of iproniazid. Among the newer compounds for which such claims have been made is N-isonicotinoyl (-N-N-benzylcarboxamidoethyl) hydrazine or Nialamide.