Romergoline (FCE 23884) is an ergoline derivative and a dopamine receptor agonist and antagonist. Its action depends on the functional state of the biological substrate, mostly related to the presence or absence of dopamine. In healthy animals, it behaves as a full dopamine antagonist, but in denervated models it behaves as an agonist. Therefore, romergoline was suggested to be potentially useful in both psychotic states and extrapyramidal diseases. In Parkinson patients, the degree of dopamine receptor stimulation was found to be insufficient to improve symptoms. Information about further development of romergoline is not available.

Clopimozide is a typical antipsychotic drug, developed by Janssen Pharmaceutica. Clopimozide belongs to diphenylbutylpiperidine class of neuroleptics, and possess an extremely long duration of action. The drug acts by binding to dopamine receptors and by inhibition of calcium channels. In a clinical trial, clopimozide exhibited a marked effect on schizophrenic target symptoms, with an absence of sedation and a low degree of extrapyramidal side-effects. Despite positive results, the drug was never marketed.

Tepirindole (also known as HR-592), an indole derivative has a high affinity for DA, 5-HT and NE receptors but has little properties to cause catalepsy. Animal experiments have shown that this compound could alleviate the adverse effect of neuroleptics such as haloperidol. Information about the current development of tepirindole is not available.

Etrabamine is a potent agonist of dopamine D2 receptors. It was being studied in the treatment of Parkinson's disease, however, its development has been discontinued.

Butaclamol is an antipsychotic drug, which was studied for the treatment of schizophrenia. This drug has never marketed and now is used in research, because of its action as a dopamine receptor-blocking agent. Butaclamol consists of the two forms: (-)-butaclamol, an inactive drug and (+)-butaclamol, a potent neuroleptic drug.

ISOSULPRIDE, a benzamide derivative, is an atypical neuroleptic.

Mesulergine, an antagonist of 5-HT2C, and dopamine receptors was studied in clinical trials for the treatment of Parkinson's disease. However, further, development was discontinued due to toxicological observations in animal experiments.

Lensiprazine (SLV314) is a potent D2 receptor antagonist in vitro and have a considerable in vitro affinity for serotonin reuptake sites. It capable of antagonizing apomorphine-induced climbing behavior, disrupting CAR activity and potentiating 5-hydroxytryptophan (5-HTP) behavior. SLV314 has also been found to antagonize amphetamine- and ketamine-stimulated locomotor activity and methylphenidate-induced gnawing and stimulated behaviors, furthermore, a significant dose discrepancy was seen between the antipsychotic and cataleptogenic effects of SLV314. Lensiprazine demonstrated putative antipsychotic and selective serotonin reuptake inhibitor potential.

Pinoxepin belongs to the dibenzoxepine series of drugs which are characterized by a 6-7-6 tricyclic nuclear structure. Clinical studies indicated that pinoxepin was a potent antipsychotic-sedative equally effective to chlorpromazine and thioridazine. Pinoxepin in studies with chronic schizophrenic patients displayed useful effects on behavior without unduly prominent side effects. In doses above 300 mg seizures are reported and more frequent changes in liver-function tests were noted than with standard drug, but below 300 mg pinoxepin was found to have side effects similar to chlorpromazine and marked sedative effects.