Haloperidol is a phenyl-piperidinyl-butyrophenone that is used primarily to treat schizophrenia and other psychoses. It is also used in schizoaffective disorder, delusional disorders, ballism, and Tourette syndrome (a drug of choice) and occasionally as adjunctive therapy in mental retardation and the chorea of Huntington disease. It is a potent antiemetic and is used in the treatment of intractable hiccups. Haloperidol also exerts sedative and antiemetic activity. Haloperidol principal pharmacological effects are similar to those of piperazine-derivative phenothiazines. The drug has action at all levels of the central nervous system-primarily at subcortical levels-as well as on multiple organ systems. Haloperidol has strong antiadrenergic and weaker peripheral anticholinergic activity; ganglionic blocking action is relatively slight. It also possesses slight antihistaminic and antiserotonin activity. The precise mechanism whereby the therapeutic effects of haloperidol are produced is not known, but the drug appears to depress the CNS at the subcortical level of the brain, midbrain, and brain stem reticular formation. Haloperidol seems to inhibit the ascending reticular activating system of the brain stem (possibly through the caudate nucleus), thereby interrupting the impulse between the diencephalon and the cortex. The drug may antagonize the actions of glutamic acid within the extrapyramidal system, and inhibitions of catecholamine receptors may also contribute to haloperidol's mechanism of action. Haloperidol may also inhibit the reuptake of various neurotransmitters in the midbrain, and appears to have a strong central antidopaminergic and weak central anticholinergic activity. The drug produces catalepsy and inhibits spontaneous motor activity and conditioned avoidance behaviours in animals. The exact mechanism of antiemetic action of haloperidol has also not been fully determined, but the drug has been shown to directly affect the chemoreceptor trigger zone (CTZ) through the blocking of dopamine receptors in the CTZ. Haloperidol is marketed under the trade name Haldol among others.

Thiothixene (trade mark Navane) belongs to a class of antipsychotics known as the first-generation antipsychotics, sometimes referred to as conventional or typical antipsychotics. Thiothixene is a thioxanthene antipsychotic which elicits antipsychotic activity by postsynaptic blockade of CNS dopamine receptors resulting in inhibition of dopamine-mediated effects; also has alpha-adrenergic blocking activity. Thiothixene is effective in the management of schizophrenia. Only cis isomer of thiothixene exerts clinical effectivity.

Thioridazine (Mellaril or Melleril) is a piperidine typical antipsychotic drug belonging to the phenothiazine drug group and was previously widely used in the treatment of schizophrenia and psychosis. Thioridazine blocks postsynaptic mesolimbic dopaminergic D1 and D2 receptors in the brain; blocks alpha-adrenergic effect depresses the release of hypothalamic and hypophyseal hormones and is believed to depress the reticular activating system thus affecting basal metabolism, body temperature, wakefulness, vasomotor tone, and emesis. Thioridazine primary use in medicine was the treatment of schizophrenia. Thioridazine was also tried with some success as a treatment for various psychiatric symptoms seen in people with dementia, but chronic use of thioridazine and other antipsychotics in people with dementia is not recommended. Thioridazine prolongs the QTc interval in a dose-dependent manner. It produces significantly less extrapyramidal side effects than most first-generation antipsychotics. Its use, along with the use of other typical antipsychotics, has been associated with degenerative retinopathies. It has a higher propensity for causing anticholinergic side effects coupled with a lower propensity for causing extrapyramidal side effects and sedation than chlorpromazine but also has a higher incidence of hypotension and cardiotoxicity. It is also known to possess a relatively high liability for causing orthostatic hypotension compared to other antipsychotics. Similarly to other first-generation antipsychotics, it has a relatively high liability for causing prolactin elevation. It is the moderate risk of causing weight gain.

Phendimetrazine is an appetite suppressant that is FDA approved for the treatment of exogenous obesity. It is clinically available anorectic agent, which display minimal interactions with monoamine transporters in vitro. On the other hand, their medications is known to be psychomotor stimulants when administered in vivo as indicated by their shared properties with illicit drugs like cocaine. The following adverse reactions are described, or described in greater detail, in other sections: Primary pulmonary hypertension; Valvular heart disease; Effect on the ability to engage in potentially hazardous tasks; Withdrawal effects following prolonged high dosage administration. Use of phendimetrazine tartrate is contraindicated during or within 14 days following the administration of monoamine oxidase inhibitors because of the risk of hypertensive crisis.

Diethylpropion is a sympathomimetic stimulant drug marketed as an appetite suppressant. Chemically, it is the N,N-diethyl analog of cathinone. Its mechanism of action is similar to other appetite suppressants such as sibutramine, phentermine and dextroamphetamine. Diethylpropion is an amphetamine that stimulates neurons to release or maintain high levels of a particular group of neurotransmitters known as catecholamines; these include dopamine and norepinephrine. High levels of these catecholamines tend to suppress hunger signals and appetite. Diethylpropion (through catecholamine elevation) may also indirectly affect leptin levels in the brain. It is theorized that diethylpropion can raise levels of leptin which signal satiety. It is also theorized that increased levels of the catecholamines are partially responsible for halting another chemical messenger known as neuropeptide Y. This peptide initiates eating, decreases energy expenditure, and increases fat storage. It is used in the management of exogenous obesity as a short-term adjunct (a few weeks) in a regimen of weight reduction based on caloric restriction.

Fluphenazine is a trifluoro-methyl phenothiazine derivative intended for the management of schizophrenia and other psychotic disorders. Fluphenazine has not been shown effective in the management of behaviorial complications in patients with mental retardation. Fluphenazine blocks postsynaptic mesolimbic dopaminergic D1 and D2 receptors in the brain; depresses the release of hypothalamic and hypophyseal hormones and is believed to depress the reticular activating system thus affecting basal metabolism, body temperature, wakefulness, vasomotor tone, and emesis.

Trimethobenzamide (trade names Tebamide, Tigan) is an antiemetic used to prevent nausea and vomiting. Trimethobenzamide is an antagonist of the D2 receptor, that affects the chemoreceptor trigger zone (CTZ) of the medulla oblongata to suppress nausea and vomiting. The oral bioavailability of trimethobenzamide is 60% to 100%. The time to peak is about 45 minutes after oral administration and; I.M. about 30 minutes after intramuscular administration. The onset action of trimethobenzamide for antiemetic effects is 10-40 minutes after oral administration and; 15-35 minutes after intramuscular administration. The duration of action is 3-4 hours. Trimethobenzamide is generally considered the most potent antiemetic that does not have effects on the serotonergic, dopaminergic, or histaminergic systems, so it has a lower likelihood of causing undesired side effects. Possible side effects include drowsiness, dizziness, headache, diarrhea, muscle cramps, and blurred vision. More serious adverse effects include skin rash, tremors, parkinsonism, and jaundice.

Trifluoperazine (Eskazinyl, Eskazine, Jatroneural, Modalina, Stelazine, Terfluzine, Trifluoperaz, Triftazin) is a typical antipsychotic of the phenothiazine chemical class used for the short-term treatment of certain types of anxiety. Trifluoperazine blocks postsynaptic mesolimbic dopaminergic D1 and D2 receptors in the brain; depresses the release of hypothalamic and hypophyseal hormones and is believed to depress the reticular activating system thus affecting basal metabolism, body temperature, wakefulness, vasomotor tone, and emesis. The primary application of trifluoperazine is for schizophrenia. Other official indications may vary country by country, but generally, it is also indicated for use in agitation and patients with behavioral problems, severe nausea, and vomiting as well as severe anxiety. Trials have shown a moderate benefit of this drug in patients with borderline personality disorder. A 2004 meta-analysis of the studies on trifluoperazine found that it is more likely than placebo to cause extrapyramidal side effects such as akathisia, dystonia, and Parkinsonism. It is also more likely to cause somnolence and anticholinergic side effects such as red-eye and xerostomia (dry mouth).

Phentermine is an amphetamine that stimulates neurons to release or maintain high levels of a particular group of neurotransmitters known as catecholamines; these include dopamine and norepinephrine. High levels of these catecholamines tend to suppress hunger signals and appetite. The drug seems to inhibit reuptake of noradrenaline, dopamine, and seratonin through inhibition or reversal of the reuptake transporters. It may also inhibit MAO enzymes leaving more neurotransmitter available at the synapse. Phentermine (through catecholamine elevation) may also indirectly affect leptin levels in the brain. It is theorized that phentermine can raise levels of leptin which signal satiety. It is also theorized that increased levels of the catecholamines are partially responsible for halting another chemical messenger known as neuropeptide Y. This peptide initiates eating, decreases energy expenditure, and increases fat storage. Phentermine is indicated in the management of exogenous obesity as a short term (a few weeks) adjunct in a regimen of weight reduction based on caloric restriction. Phentermine hydrochloride is a sympathomimetic amine with pharmacologic activity similar to the prototype drugs of this class used in obesity, the amphetamines. Actions include central nervous system stimulation and elevation of blood pressure. Tachyphylaxis and tolerance have been demonstrated with all drugs of this class in which these phenomena have been looked for.

Perphenazine is a relatively high potency phenothiazine that blocks dopamine 2 receptors predominantly, but also may possess antagonist actions at histamine 1 and cholinergic M1 and alpha 1 adrenergic receptors in the vomiting center leading to reduced nausea and vomiting. The drug was approved by FDA for the treatment of schizophrenia and control of severe nausea and vomiting (either alone or in combination with amitriptyline hydrochloride). Perphenazine is extensively hepatic to metabolites via sulfoxidation, hydroxylation, dealkylation, and glucuronidation; primarily metabolized by CYP2D6 to N-dealkylated perphenazine, perphenazine sulfoxide, and 7-hydroxyperphenazine (active metabolite with 70% of the activity of perphenazine) and excreted in the urine and feces.