As with many psychiatric drugs, the discovery of irreversible MAOIs was serendipitous. While being used as an antitubercular agent in the 1950s, iproniazid—a derivative of the hydrazine compound isocarboxazid—was observed to have significant antidepressant properties. Almost at the same time as the discovery of TCAs such as amitriptyline and imipramine (which were also discovered by chance), MA...
