GBR-12935 (1-{2-benzhydryloxyethyl}-4-(3-phenylpropyl)piperazine) is a potent and selective inhibitor of dopamine transporter. Gist-Brocades originally initiated studies of GBR-12935 for the treatment of cocaine dependence. Tritium-labeled GBR-12935 may be used in radioligand binding studies. GBR-12935 is considered to be the metabolite of vanoxerine, another piperazine dopamine uptake inhibitor.

Gepirone (brand name Travivo) is an investigational azapirone antidepressant and anxiolytic drug in development for the treatment of major depressive disorder but has yet to be marketed. Like other azapirones, it acts as a selective partial agonist of the 5-HT1A receptor. Gepirone has been under development in the U.S. in an extended release form (referred to as Gepirone ER). It has been rejected multiple times by the FDA during the drug approval process and Phase III studies evaluating its use in the treatment of MDD were prematurely terminated. These were the initial Phase III studies of gepirone ER in MDD, and the effective dose range had not been determined. In March 2016, the FDA reversed its decision and gave gepirone ER a positive review, clearing the way for the drug to finally gain market approval in the U.S. In addition to its antidepressant and anxiolytic properties, gepirone has been found to improve symptoms of sexual dysfunction in men and women, similarly to the marketed 5-HT1A receptor agonist flibanserin. The pro-sexual effects appear to be independent of its antidepressant and anxiolytic effects. Mechanism of action studies have demonstrated that gepirone possesses a much greater selectivity for 5-HT1A receptors over dopamine D2 receptors. Long-term studies have shown that gepirone has a differential action at presynaptic (agonist) and post-synaptic (partial agonist) 5-HT1A receptors. Treatment with gepirone ER desensitizes presynaptic 5-HT1A receptors, which decreases serotonin autoregulatory inhibition and enhances activation of postsynaptic 5-HT1A receptors. As a partial agonist gepirone ER acts as an agonist when endogenous serotonin is not present and as an antagonist when endogenous serotonin is present. Overall, gepirone ER increases serotonin production when insufficient amounts are present, and decreases serotonin production when excess amounts are present. Gepirone has been tested in Phase II clinical trial as antidepressant medication for pharmacotherapy for cocaine dependent subjects.

Citicoline (CDP-choline; cytidine 5'-diphosphocholine) is a novel nutrient with a broad spectrum of benefits for conditions associated with symptoms of neurological dysfunction shows promise of clinical efficacy in elderly patients with cognitive deficits, inefficient memory, and early-stage Alzheimer's disease. Citicoline has also been investigated as a therapy in stroke patient. Despite it was approved in some countries for treatment Traumatic Brain Injury (TBI), the use of this drug for acute TBI seems to have no field of support anymore, whereas it may have some benefits in improving the neuro-cognitive state in chronic TBI patients. It's also recommended to keep in mind acute interventions like Psychological First Aid (PFA) during acute TBI management. Citicoline plays several important roles in human physiology, including enhancement of structural integrity and signaling for cell membranes, support of acetylcholine synthesis, and synthesis of betaine, a methyl donor. The precise mechanism of action of Citicoline to treat disease is unknown, but was confirmed, that drug might increase phosphatidylcholine (PtdCho) synthesis and might reverse PtdCho loss. In addition, was shown, that citicoline modulates phospholipids metabolism and neurotransmitter levels and appears to improve cognition in some central nervous system disorders such as bipolar disorder and cocaine dependence. Bipolar disorder is associated with the highest rates of substance abuse of any psychiatric disorder. Cocaine use is particularly common in patients with bipolar disorder.

Levlofexidine is R-enantiomer of a α2A adrenergic receptor agonist Lofexidine. Levlofexidine (as a component of Lofexidine) can be used as a short-acting anti-hypertensive but is mostly used to help relieve symptoms of heroin or opiate withdrawal in opiate dependency. Lofexidine is approved in the United Kingdom but is still undergoing clinical trials in the United States. Levlofexidine showed an approximately 9-fold higher affinity than Dexlofexidine for the alpha 2-adrenoceptor-like binding sites in rat brain membranes identified by [3H]-clonidine and was 4 times more potent at displacing [3H]-prazosin from alpha 1-adrenoceptors. The possibility of using lofexidine to treat alcohol addiction withdrawal symptoms has been investigated and has not yet been shown to be an effective treatment.

Amperozide (FG 5606, N-ethyl-4-[4',4'-bis(p-fluorophenyl)butyl]-1-piperazine-carboxamide) is an atypical antipsychotic drug which has relatively weak in vitro affinity for striatal dopamine2 (D2) receptors and a strong affinity for the cortical 5-HT2A receptor. It was shown in animal models, that amperozide could attenuate craving for cocaine. In addition, this drug was studied in patients with schizophrenia and was shown, that several patients had improvements as was assessed by the Clinical Global Improvement Scale. However, these studies were discontinued.