Timiperone is a neuroleptic agent that was developed in Japan. Timiperone has a potent antipsychotic activity, which is comparable to other butyrophenones such as haloperidol (HAL). Timiperone has a five-eight-times higher affinity to dopamine receptors and a 15-times higher affinity to serotonin receptors than those of HAL. Clinical trials have suggested that TIM has a specific action against negative symptoms such as lack of initiative or blunted affect as well as positive symptoms such as delusions and hallucinations in schizophrenics.

Medifoxamine, an antidepressive drug, preferentially inhibits dopamine reuptake. It was marketed in France, but because of the hepatotoxicity, then was withdrawn.

Raclopride is a salicylamide neuroleptic, that acts as a selective antagonist of D2 dopamine receptors both in vitro and in vivo. Tritium-labelled raclopride has properties that demonstrate its usefulness as a radioligand for the labelling of dopamine-D2 receptors : 3H-Raclopride has a high affinity for the rat and human dopamine-D2 receptors, the non-specific binding of 3H-raclopride is very low, not exceeding 5% of the total binding and the distribution of the 3H-raclopride binding sites in the brain closely correlates with the dopaminergic innervation. The binding of 3H-raclopride is blocked by dopamine-D2 agonists and antagonists, while the D1 agonist SKF 38393 and the Dl antagonist SCH 23390 have much less potency. The interaction of dopamine with 3H-raclopride binding results in a shallow competition curve, which suggests that 3H-raclopride, similar to other dopamine-D2 radioligands, labels both high and low agonist affinity states of the dopamine-D2 receptor. The in vivo receptor binding studies performed with 3H-raclopride also demonstrate its favorable properties as a dopamine-D2 receptor marker in vivo In contrast to some other compounds used as radioligands, raclopride enters the brain readily and binds with a low component of non-specific binding in all dopamine-rich brain areas. A saturation curve may be achieved in vivo binding studies since injections of increasing concentrations of 3H-raclopride appears to be saturated at concentrations above 25 mkCi (corresponding to approximately 5 nmol/kg). Raclopride antagonizes apomorphine-induced hyperactivity in the rat at low doses (ED50 = 130 nM/kg i.p.) but induces catalepsy only at much higher doses (ED50 = 27 mkM/kg i.p.). Radiolabelled raclopride has been used as a ligand for in vitro and in vivo autoradiography in rat and primate brains. Raclopride C 11 is used with positron emission tomography (PET) as a clinical research tool to determine dopamine type 2 (D 2) receptor density in the human brain under normal and pathological conditions. For example, raclopride C 11 used in PET studies has served to confirm the age-related decrease in striatal dopamine D2 receptor density, which may be associated with a decline in the motor as well as cognitive functions. In patients with Alzheimer's disease, raclopride C 11 may be used to examine neuroreceptor distribution and quantities, which may help in the analysis of degenerative alterations of neuron populations and neuroreceptor systems in patients with this disease. In Huntington's disease, in which degeneration of neostriatal interneurons occurs (postsynaptic to the dopaminergic input), specific binding of raclopride C 11 to D 2 receptors may serve as one of the parameters in predicting performance in cognitive tasks.

Zuclopenthixol is indicated the management of the manifestations of schizophrenia and other mental illnesses with disturbances in thinking, emotional reactions and behaviour. It is also used to treat the manic phase of manic depressive illness. Zuclopenthixol, a thioxanthene derivative, has high affinity for both dopamine D1 receptors and dopamine D2 receptors. Zuclopenthixol also has high affinity for α1-adrenergic and 5-HT2 receptors. Zuclopenthixol (CLOPIXOL®) is avavilable in the form of tablets and solution for intramuscular injections.

Cinnarizine is a piperazine derivative with antihistaminic, antiserotonergic, antidopaminergic, and calcium channel-blocking activities. It inhibits calcium translocation across the vestibular sensory cells in the ampullae and maintains endolymph flow by preventing constriction of the stria vascularis. It is currently used for the treatment of nausea, vomiting, and vertigo caused by Meniere’s disease and other vestibular disorders. Cinnarizine is also used for prevention and treatment of motion sickness. Chronic use of cinnarizine may induce extrapyramidal symptoms.

Etoperidone is an atypical antidepressant introduced in Europe in 1977. The activity of etoperidone is made mainly by its major metabolite 1-(3'-chlorophenyl)piperazine (mCPP). mCPP binds with different affinity to most of the serotonergic receptors and adrenergic receptors. This metabolite is an agonist of 5-HT2c and an antagonist of 5-HT2a. Part of etoperidone structure contributes to the activity in the α-adrenergic receptors. Etoperidone has been studied for the treatment of depression, tremors in Parkinson, extrapyramidal symptoms and male impotence. It is not certain if it was ever approved and marketed but its current status is withdrawn.

Clebopride is a dopamine antagonist drug. It is used to treat functional gastrointestinal disorder such as nausea or vomiting. Unchanged parent drug was the most abundant compound in human urine. Major metabolites included the hydroxylation at benzyl group to yield carbinolamine and its further N-dealkylation product, and the piperidine ring hydroxylation/oxidation metabolite (a lactam).

Alentemol (U-66444B) is a selective dopamine agonist acting at presynaptic receptors to inhibit the release of dopamine. In preclinical studies the compound caused hypothermia in mice and inhibited amphetamine-stimulated omtor activity in mice. U-66444B was investigated by Upjohn Company for the treatment of schizophrenia, but the development of the drug was discontinued.

Budipine is an antiparkinsonian drug, which was developed by Byk Gulden (now Takeda) for the treatment of Parkinson's disease. The drug has multiple mechanisms of action: it was found to interfere with dopamine biosynthesis, mainly by inhibiting MAO-B enzyme and stimulating aromatic L-amino acid decarboxylase. Also the drug inhibits the dopamine re-uptake and has weak affinity to NMDA and muscarinic receptors. Budipine passes the blood-brain barrier, is metabolized by hydroxylation, and is excreted by both in urine and feces within 24 h.

Remoxipride is a substituted benzamide. It is a weak, but relatively selective, central dopamine D2-receptor antagonist and appears to have preferential affinity for extrastriatal dopamine D2-receptors. It also has marked affinity for central sigma receptors. It was introduced by Astra (Roxiam) at the end of the eighties and was prescribed as an atypical antipsychotic. Remoxipride was withdrawn from the market worldwide by Astra because of several cases of aplastic anaemia associated with the drug.