Quetiapine and haloperidol

The effects of haloperidol and quetiapine on serum prolactin concentrations have been compared in 35 patients with schizophrenia during a drug-free period for at least 2 weeks in a randomized study (475). There was no significant difference in prolactin concentration between the groups at the start of the study control prolactin concentrations were significantly lower with quetiapine than with haloperidol. Two patients taking haloperidol had galactorrhea related to hyperprolactinemia. 

Because of the frequency of co-administration of benzodiazepines with neuroleptic drugs, it is important to consider possible adverse effects that can result from such combinations. In a brief review, emphasis has been placed on pharmacokinetic interactions between neuroleptic drugs and benzodiazepines, as much information on their metabolic pathways is emerging (166). Thus, the enzyme CYP3A4, which plays a dominant role in the metabolism of benzodiazepines, also contributes to the metabolism of clozapine, haloperidol, and quetiapine, and neuroleptic drug plasma concentrations can rise. Intramuscular levomepromazine in combination with an intravenous benzodiazepine has been said to increase the risk of airways obstruction, on the basis of five cases of respiratory impairment the doses of levomepromazine were higher in the five cases that had accompanying airways obstruction than in another 95 patients who did not (167). 

Tardive dyskinesia refers to uncontrollable facial movements. It is more likely to occur in the elderly. Tardive dyskinesia is commonly associated with the use of antipsychotic drugs, such as haloperidol. The atypical antipsychotics, such as clozapine, olanzapine, risperidone and quetiapine are less likely to cause tardive dyskinesia. 

In the Expert Consensus survey, the respondents endorsed risperidone, olanzapine, and quetiapine, in that order, followed by high-potency traditional antipsychotics, for managing self-injury. A placebo-controlled study comparing risperidone with a classical antipsychotic, such as haloperidol, could provide valuable data for this field. 

Arvanitis LA, Miller BG Multiple fixed doses of Seroquel (quetiapine) in patients with acute exacerbation of schizophrenia a comparison with haloperidol and placebo. The Seroquel Trial 13 Study Group. Biol Psychiatry 42 233-246, 1997... 

D2 receptor, albeit with different specificity. Older examples of dopamine antagonists are chlorpromazine, haloperidol and many derivatives of these prototype compounds. Newer antipsychotic drugs such as risperidone, olanzapine and quetiapine have retained this mechanism of action, although no longer exclusively. 

Arvanitis and Miller (129) reported a multiple fixed-dose, placebo-controlled, double-blind study of quetiapine in comparison with haloperidol and placebo in acutely exacerbated patients with chronic schizophrenia. Quetiapine was administered in five doses 75, 150, 300, 600, and 750 mg/day haloperidol was given at 12 mg/day. The study design had slightly more than 50 patients in each group. The 75-mg dose of quetiapine was clearly less efficacious than the higher doses. Doses of 150 to 750 mg/day were superior to placebo and comparable with haloperidol in reducing positive symptoms and 300 mg/day was superior to placebo and comparable with haloperidol for negative symptoms. 

Lower potency neuroleptics, such as thioridazine and chlorpromazine, have a decreased incidence of EPS when compared with higher potency agents, such as haloperidol or fluphenazine. Novel agents, such as clozapine and quetiapine, are virtually devoid of EPS effects when given at their recommended dosing range. 

Hyperlipidemia associated with antipsychotic drugs has been reviewed (SEDA-29, 64). Haloperidol and the atypical antipsychotic drugs ziprasidone, risperidone, and aripiprazole would be associated with lower risks of hyperlipidemia, whereas chlorpromazine, thioridazine, and the atypical drugs quetiapine, olanzapine, and clozapine would be associated with higher risks. However, severe clozapine-induced hypercholesterolemia and hypertriglyceridemia has been reported in a patient taking clozapine (55). 

Rosengarten, H. Quartermain, D. 2002, Effect of prenatal administration of haloperidol, risperidone, quetiapine and olanzapine on spatial learning and retention in adult rats, Pharmacol.Biochem.Behav., vol. 72, no. 3, pp. 575-579. 

Jarskog et al. (2007) studied the effects of haloperidol, clozapine, and quetiapine on numerous so-called apoptotic markers to study the impact of these drugs on apoptosis. Essentially, they examined the neurotoxicity of neuroleptics, specifically their capacity to induce cell deterioration typical of the process of cell death. They found that the neuroleptics, both the older ones and the atypicals, caused activation of caspase-3, a marker for apoptosis. They tried to reassure their readers that this activity was probably non-lethal. ... 

Most antipsychotics,but also many non-an-tipsychotic drugs, reverse deficits in PPI induced by amphetamine or apomorphine (152, 153). In contrast, Dg receptor antagonists such as haloperidol fail to reverse deficits in PPI induced by PCP or dizocilpine (153-156), while such deficits are, at least in part, reversed by clozapine (156), remoxipride (157), olanzapine (158), and quetiapine (155). Risperidone fails to reverse the effect of PCP (155), but it antagonizes the disruption of PPI induced by the 5-HT2A agonist DOI (150,153). 

Rats reared in isolation after weaning also experience deficits in PPI (159) and decreased social interaction. This effect has been attributed to enhanced dopaminergic activity (160). Isolation rearing deficits are maximal at puberty (161,162) and thus parallel the ontog-eny of schizophrenia in humans. The disruption of PPI in young rats reared in isolation is reversed by a broad spectrum of antipsychotic drugs including haloperidol, risperidone, clozapine, olanzapine, and quetiapine (153,163). 

The same group of antipsychotic drugs have been evaluated for their effects on working memory (276,277) in a visual spatial version of the delayed non-matching to position paradigm (278,279). Haloperidol and risperidone exhibit marked inhibitory effects in low doses, whereas considerably higher doses of clozapine, olanzapine, and ziprasidone are required to produce similar effects (276). Sertindole and quetiapine are inactive at the doses tested (276). Long-term treatment reveals a continued memory impairment of memory by haloperidol, the development of tolerance to the effects of clozapine on memory, and continued lack of impairment by sertindole (277). 

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