Common mechanism of action of biochemically "specific" antidepressants

NE turnover in depressed patients treated with three drugs which have specifically different primary biochemical effects is compared before and after treatment. Turnover is quantitated as the sum of NE and its major metabolites excreted in the urine using a new mass spectrometric assay. Clorgyline , a MAOI specific for Type A; desipramine, a selective NE uptake inhibitor; and zimelidine, a selective 5HT uptake inhibitor, were used. All three antidepressants, including zimelidine, reduced NE turnover although producing very different effects on the metabolic profile of NE. It remains likely that effects on NE are related to therapeutic effect.