Neuroleptics classes

The answer is a. (Katzung, pp 471, 473, 482.) The phenothiazines as a class are the most potent anticholinergics of the neuroleptics. Tolerance to their anticholinergic effects occurs in most patients Cholinomimetic agents may be used to overcome symptoms that persist. 

Whatever the underlying causes may be, neuroleptic medications are the most effective treatment for schizophrenia. All antipsychotic medications have some form of dopamine receptor antagonism and they are distinguished by their chemical class. The phenothiazines include chlorpromazine (Thorazine), thioridazine (Mellaril), mesoridazine (Serentil), trifluoperazine (Stelazine), fluphenazine (Prolixin), and prochlorperazine (Compazine). The thioxanthenes include chlorprohixine (Taractan) and thiothixene (Navane). Butyrophenones are represented by haloperidol (Haldol). Loxapine (Loxitane) is a dibenzoxapine, and molindone (Moban) is a dihydroindolone. 

The conventional (or classical) neuroleptics comprise two classes of compounds with distinctive chemical structures 1. the phenothiazines derived from the antihistamine promethazine (prototype chlorpromazine), including Ltillmann, Color Atlas of Pharmacology 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 

It also seems plausible that antipsychotic drugs competitively bind with dopamine receptors and block the action of dopamine on corresponding receptor sites, thus lowering psychotic activity. Central dopamine receptors are subdivided into Dj, D2, and according to some sources, Dj receptors. These receptors have a high affinity for dopamine, but they differ in sensitivity to neuroleptics of various chemical classes. For example, drugs of the phenothiazine series are nonselective competitive Dj and D2 antagonists. Unlike phenoth-iazines, antipsychotics of the butyrophenone series such as haloperidol display selective action only on D2 receptors. 

Multitarget forensic applications of HPLC for other drug classes are also available in the literature. Josefsson et al. [77] applied HPLC-MS-MS to the determination of 19 neuroleptics and their major metabolites in human tissues and body fluids. Optimal separation was achieved using a cyano column within a 9 min gradient run. Detection was curried out in SRM reaching LQDs down to the lower ng/mL level, although more than a 10-fold difference in signal response was observed between analytes. The method was subjected to partial validation only. 

The other group within this class of dibenzazepines are formed by agents which are related to clozapine. Clozapine is an atypical antipsychotic which is used for the treatment of schizophrenia. It is primarily indicated for schizophrenic patients with predominantly negative symptoms. Its indication can be extended to those patients that have shown to be refractory to the conventional neuroleptics. It can also be substituted for other antipsychotics in... 

Fluphenazine, a typical neuroleptic of the phenothi-azine class, has been less widely used for treatment of tics than haloperidol or pimozide. A controlled trial of haloperidol, fluphenazine, and trifluoperazine found comparable tic-reducing efficacy, but greater sedation and extrapyramidal side effects for haloperidol fluphenazine was the best tolerated (Borison et al., 1982). In an open-label trial with 21 subjects who had an unsatisfactory response to haloperidol, fluphenazine had a superior side effect profile to that of haloperidol in the dose range employed (mean dose of fluphenazine, 7 mg/day, range 2-15 mg/day) (Goetz et al., 1984). In this group selected for an unsatisfactory response to haloperidol, 11 of the 21 subjects (52%) had a better response to fluphenazine than haloperidol, 6 subjects had a comparable response, and 2 subjects preferred haloperidol. 

Tiapride and sulpiride are neuroleptics of the substituted benzamide class. These selective Dj blockers have weak antipsychotic properties and are not available in the United States, although they are commonly used in Europe for the treatment of tics. In a pair of 6-week controlled trials involving 27 children with TS, at doses ranging from 4 to 6 mg/kg/day, tiapride was superior to placebo and produced a 30%-44% decrease in videotaped tic counts (Eggers et ah, 1988). 

The major psychotropic drug classes (stimulants, ttj agonists, antidepressants and neuroleptics) that have been studied in the preschool population are summarized below. 

Atypical neuroleptics. Because of the limited effectiveness and safety of conventional neuroleptics in TS, clinicians have turned to a new generation of neuroleptics that have been introduced for the treatment of schizophrenia. Risperidone, a member of a class of antipsychotics that blocks both DA and serotonin receptors, has been established as superior to placebo and equal, or superior, to haloperidol in the treatment of schizophrenia (Chouinard et al. 1993 Marder and Meibach 1994]. Risperidone has a more favorable side-effect profile than that of conventional neuroleptics and may have less potential for producing tardive dyskinesia. Compared with haloperidol, fewer extrapyramidal side effects are observed with risperidone in doses of 6 mg/ day or less. As encouraging reports appear in the literature (Lombroso et al. 1995 Stamenkovic et al. 1994 van der Linden et al. 1994], risperidone is currently being widely used by clinicians to treat tic disorders. 

Schizophrenia is usually treated with a class of medications called antipsychotics, or neuroleptics, that act to reduce the activity of the neurotransmitter dopamine, which may be overactive in the brains of schizophrenics. Commonly used antipsychotic medications include risperidone (Risperdal ),... 

Involuntary movement disorders also respond well to this class of drugs. These include restless leg syndrome, akathisia associated with neuroleptic use, choreiform disorders, and myoclonus. 

The results of such studies suggest that the major classes of neuroleptics in therapeutic use owe their activity to their ability to block D2 and/or D, receptors, particularly in the mesocortical and mesolimbic regions of the brain. Side effects, such as parkinsonism and increased prolactin release, would seem to be associated with the antagonistic effects of these drugs on D2 and/or Dj receptors in the nigrostriatal and tuberoinfundibular systems. 

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