Seproxetine, also known as (S)-norfluoxetine, is a selective serotonin reuptake inhibitor (SSRI). It is the most important active metabolite of the widely used antidepressant fluoxetine, but little is known about its pharmacological actions. Seproxetine was being investigated by Eli Lilly and Company as an antidepressant; however, a cardiac side effect was noted and development was discontinued.

Diclofensine is an antidepressant with equipotent inhibitive effects on the neuronal uptake of norepinephrine (NE), serotonin, and dopamine. It is devoid of monoamine-releasing or monoaminoxidase-inhibiting properties. Diclofensine was found to be an effective antidepressant in human trials, with relatively few side effects, but was ultimately dropped from clinical development.

Oxidopamine (6-Hydroxydopamine) is an antagonist of the neurotransmitter dopamine with potential antineoplastic activity. 6-Hydroxydopamine (6-HOD) can be taken up by selective adrenergic terminals, thereby causing acute degeneration of adrenergic terminals that leads to depletion of norepinephrine, and of dopamine in the dopamine-sensitive sites. This agent is auto-oxidated at physiological pH that leads to the formation of reactive free radicals, thereby leading to cytotoxicity in neural cells. 6-Hydroxydopamine is often used to induce CNS and sympathetic neural lesions that model aging and various nervous disorders in animal systems. The growth of C-1300 neuroblastoma was markedly slowed in 6-hydroxydopamine-treated mice. The growth of the A-10 breast adenocarcinoma was also significantly retarded in 6-hydroxydopamine-treated mice but the growth of B-16 melanoma was not affected.

DOV-102,677 is a “Triple” Monoamine Neurotransmitter Uptake Inhibitor being developed by Merck for treating the major depressive disorder. In preclinical studies, DOV 102,677 increased extracellular levels of DA and 5-HT in the prefrontal cortex at 100 min after administration. DA levels were stably increased for the duration (240 min) of the study, but serotonin levels declined to baseline by 200 min after administration. NE levels increased linearly to a maximum of 240 min post-dosing. Consistent with these increases in NE levels, the density of β-adrenoceptors was selectively decreased in the cortex of rats treated with DOV 102,677. DOV 102,677 dose-dependently reduced the amount of time spent immobile by rats in the forced swim test, a model predictive of antidepressant activity, with a minimum effective dose (MED) of 20 mg/kg and a maximal efficacy comparable to imipramine. However, phase I clinical trials for treatment Depression in the USA was discontinued. Instead of being developed for depression, DOV-102,677 is being developed for the treatment of alcoholism.