Antipsychotics thioridazine

Dubitsky, G.M. (2000) Clinically important QT interval prolongation with three antipsychotics thioridazine, pimozide, sertindole, FDA. 

Low-potency antipsychotics include thioridazine, mesoridazine, and chlorpromazine. 

Current antipsychotics used to treat patients are divided into two classes the first generation antipsychotics (FGA) or typicals (e.g., chlorproma-zine, haloperidol, thioridazine, and loxapine) and the second generation antipsychotics (SGA) or atypicals (i.e., clozapine, olanzapine, quetiapine, risperidone, aripiprazole, ziprasidone, and asenapine). 

The answer is b. (Katzung, p 4822) Haloperidol, a butyrophenone, is by far the most likely antipsychotic to produce extrapyramidal toxicides Other agents, such as piperazine (an aromatic phenothiazine), thiothixene (a thioxanthene), and pimozide (a diphenylbutyropiperidine) are comparitively less likely to produce extrapyramidal toxicity than haloperi-dol. The antagonism of dopamine in the nigrostriatal system might explain the Parkinson-like effects Both haloperidol and pimozide act mainly on D2 receptors, whereas thioridazine and piperazine act on ooadrenergie receptors, and have a less potent but definite effect on D2 receptors. 

If a change in antipsychotic therapy is required, risperidone, molindone, thioridazine, haloperidol, pimozide, trifluoperazine, and fluphenazine may be considered. 

Milnes, J.T., Witchel, H.J., Leaney, J., Leishman, D. and Hancox, J.C. (2006) hERG K+ channel blockade by the antipsychotic drug thioridazine an obligatory role for the S6 helix residue F656. Biochemical and Biophysical Research Communications, 351, 273-280. 

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. 

Typical Antipsychotics. The high potency antipsychotic haloperidol (Haldol) and low potency antipsychotics chlorpromazine (Thorazine) and thioridazine (Mellaril) have also been used to treat ADHD. Although they provide a tranquilizing effect (they are in fact sometimes called major tranquilizers ) that can reduce hyperactivity and impulsivity, antipsychotics remain markedly less effective than stimulants. Antipsychotics do not noticeably improve attention in patients with ADHD, and at this time the typical antipsychotics cannot be considered a reasonable monotherapy in uncomplicated ADHD. 

Antipsychotics. Antipsychotic medications are also called major tranquilizers. It is for the tranquilizing effect that they have been used to treat agitation. The earliest antipsychotics, especially thioridazine (Mellaril), proved to be effective in reducing agitation however, this comes at the price of further impairing cognition due to its profound anticholinergic effects. 

Several studies have evaluated the use of low doses of the typical antipsychotics. These include studies of high potency antipsychotics such as haloperidol, medium potency antipsychotics such as loxapine, and low potency antipsychotics such as chlorpromazine and thioridazine. In general, the studies have shown that antipsychotics reduce impulsivity and protect from psychotic decompensation. 

Thioridazine (Mellaril) Antipsychotic Thiothixene (Navane) Antipsychotic Tiagabine (Gabatril) Anticonvulsant... 

Tardive dyskinesia can occur in manic patients on neuroleptics alone, the frequency may be greater than in schizophrenics who are more likely to be on continuous medication. One possible explanation for this lies in the fact that neuroleptics are often administered to manic patients for short periods only, sufficient to abort the active episode, and then abruptly stopped. Thus high doses of neuroleptics are separated by drug-free periods, leading to a situation most likely to precipitate tardive dyskinesia. The recent increase in prescribing high potency neuroleptics such as haloperidol instead of low potency drugs such as chlorpromazine or thioridazine has undoubtedly increased the frequency of tardive dyskinesia. Clearly, use of the atypical antipsychotics with the very low frequency of EPS makes them the treatments of choice. 

Risperidone and olanzapine have been widely used in patients with dementia exhibiting behavioural problems. Following the withdrawal of thioridazine from the market, old age psychiatrists and GPs were increasingly atypical antipsychotics, in particular risperidone as it was the only atypical which had been examined in randomised clinical trials (RCTs) with the elderly. In 2004, the advised that both risperidone... 

From the chemical point of view antipsychotic drugs are subdivided into six chemical groups, as well as to the group of non-classifiable drugs. They are phenothiazines (chlorpromazine, promazine, triflupromazine, acetophenazine, fluphenazine, perphenazine, prochlorpherazine, trifluoperazine, mesoridazine, and thioridazine), thioxanthenes... 

In terms of antipsychotic activity, thioridazine is inferior to aminazine. It is most effective in mental and emotional disorders accompanied by fear, stress, and excitement. It is prescribed for varions forms of schizophrenia, psychosis, and neurosis. The most common synonyms are conapax and mellaril. 

Contraindications for antipsychotic therapy are few they may include Parkinson s disease, hepatic failure, hypotension, bone marrow depression, or use of CNS depressants. Overdoses of antipsychotics are rarely fatal, except for thioridazine, which is associated with major ventricular arrhythmias, cardiac conduction block, and sudden death. For other agents gastric lavage should be attempted even if several hours have elapsed since the drug was taken, because gastrointestinal motility is decreased and the tablets may still be in the stomach. Moreover, activated charcoal effectively binds most of these drugs and can be followed by a saline cathartic. The hypotension often responds to fluid replacement or pressor agents such as norepinephrine. 

There are several antipsychotics that are substrates to CYP2D6 (von Bahr et ah, 1991 Jerling et ah, 1996 Ring et ah, 1996 (Fang and Gorrod, 1999 Flockhart and Oesterheld, 2000) (Table 26.3). Moreover, several antipsychotics may act as inhibitors of CYP2D6-mediated biotransformation. These include thioridazine, chlorpromazine, haloperidol, fluphenazine, and pimozide (Desta et ah, 1998 Shin et ah, 1999). Of particular salience is the fact that the serotonin selective reuptake inhibitors (SSRIs) fluoxetine and paroxetine are metabolized to a significant extent by this isoenzyme. 

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