The metabolic pathways of tianeptine, a new antidepressant, in healthy volunteers.

The metabolism of tianeptine, a novel antidepressant that presents original neurochemical properties, was studied after a single oral administration of radioisotopically (14C) labeled compound to six healthy male volunteers. After 7 days, approximately 66% of the dose was eliminated by renal excretion (55% during the first 24 hr). Tianeptine is extensively metabolized, and 24 hr after the administration, the unchanged molecule contributed in urine for less than 3% of the administered dose. Chromatographic and mass spectral studies showed that beta-oxidation of the amino acid side chain is the major route of biotransformation for tianeptine. Three major metabolites, accounting for 29% of the dose, were products of beta-oxidation. The metabolite profiles of tianeptine in feces and plasma were qualitatively similar to that in urine.