STUDIES ON THE HYPERGLYCAEMIA INDUCED BY CHLORPROMAZINE IN RATS

Atypical Antipsychotics and Metabolic Syndrome: From Molecular Mechanisms to Clinical Differences

Atypical antipsychotics (AAPs) are commonly prescribed medications to treat schizophrenia, bipolar disorders and other psychotic disorders. However, they might cause metabolic syndrome (MetS) in terms of weight gain, dyslipidemia, type 2 diabetes (T2D), and high blood pressure, which are responsible for reduced life expectancy and poor adherence. Importantly, there is clear evidence that early metabolic disturbances can precede weight gain, even if the latter still remains the hallmark of AAPs use. In fact, AAPs interfere profoundly with glucose and lipid homeostasis acting mostly on hypothalamus, liver, pancreatic β-cells, adipose tissue, and skeletal muscle. Their actions on hypothalamic centers via dopamine, serotonin, acetylcholine, and histamine receptors affect neuropeptides and 5'AMP-activated protein kinase (AMPK) activity, thus producing a supraphysiological sympathetic outflow augmenting levels of glucagon and hepatic glucose production. In addition, altered insulin secretion, dyslipidemia, fat deposition in the liver and adipose tissues, and insulin resistance become aggravating factors for MetS. In clinical practice, among AAPs, olanzapine and clozapine are associated with the highest risk of MetS, whereas quetiapine, risperidone, asenapine and amisulpride cause moderate alterations. The new AAPs such as ziprasidone, lurasidone and the partial agonist aripiprazole seem more tolerable on the metabolic profile. However, these aspects must be considered together with the differences among AAPs in terms of their efficacy, where clozapine still remains the most effective. Intriguingly, there seems to be a correlation between AAP's higher clinical efficacy and increase risk of metabolic alterations. Finally, a multidisciplinary approach combining psychoeducation and therapeutic drug monitoring (TDM) is proposed as a first-line strategy to avoid the MetS. In addition, pharmacological treatments are discussed as well.

Antipsychotics and glucose metabolism: how brain and body collide

Since the serendipitous discovery of the first antipsychotic (AP) drug in the 1950s, APs remain the cornerstone of treatment for schizophrenia. A shift over the past two decades away from first-generation, conventional APs to so-called "atypical" (or 2nd/3rd generation) APs parallels acknowledgment of serious metabolic side-effects associated in particular with these newer agents. As will be reviewed, AP drugs and type 2 diabetes are now inextricably linked, contributing to the three- to fivefold increased risk of type 2 diabetes observed in schizophrenia. However, this association is not straightforward. Biological and lifestyle-related illness factors contribute to the association between type 2 diabetes and metabolic disease independently of AP treatment. In addition, APs have a well-established weight gain propensity which could also account for elevated risk of insulin resistance and type 2 diabetes. However, compelling preclinical and clinical evidence now suggests that these drugs can rapidly and directly influence pathways of glucose metabolism independently of weight gain and even in absence of psychiatric illness. Mechanisms of these direct effects remain poorly elucidated but may involve central and peripheral antagonism of neurotransmitters implicated not only in the therapeutic effects of APs but also in glucose homeostasis, possibly via effects on the autonomic nervous system. The clinical relevance of studying "direct" effects of these drugs on glucose metabolism is underscored by the widespread use of these medications, both on and off label, for a growing number of mental illnesses, extending safety concerns well beyond schizophrenia.

Evaluation of Crimean-Congo hemorrhagic fever virus in vitro inhibition by chloroquine and chlorpromazine, two FDA approved molecules

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We analyzed the anti-CCHFV potential of the chloroquine and chlorpromazine molecules.

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They inhibited CCHFV in Vero and Huh7 cells: selectivity index ranging from 3 to 35.

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We analyzed the anti-CCHV potential of the combinations.

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Combinations of ribavirin and chloroquine or chlorpromazine were synergistic.

Crimean-Congo hemorrhagic virus (CCHFV) causes hemorrhagic fever with high case mortality rates and is endemic in south-eastern Europe, Africa, and Asia. The limited catalog of specific treatment, highlight the necessity to look for additional therapeutic solutions.

Previous experiments suggested that CCHFV enters the cells via a clathrin dependent pathway. Therefore, we have evaluated the potential anti-CCHFV activity of several molecules targeting this entry possibility. We identified two molecules chloroquine and chlorpromazine. Neutralization and virus yield reduction assays were tested in Vero E6 and Huh7 cells on two different CCHFV strains. Several combinations, including ribavirin, were assayed to test a potential synergistic effect.

The two molecules inhibited CCHFV, and depending on the virus and the cell lines, the 50% inhibitory concentration (IC₅₀) values for chloroquine and chlorpromazine ranged from 28 to 43 and 10.8–15.7 μM, respectively. Time-of-addition studies demonstrated that these molecules had a direct effect on CCHFV infectivity and spread. The antiviral activity of the two molecules was still effective even when added up to 6 h post-infection and up to 24 h. The selectivity index ranging from 3 to 35 lead us to evaluate combinations with ribavirin. Combinations of ribavirin and chloroquine or chlorpromazine were synergistic against CCHFV. Though the low chlorpromazine selectivity index suggests the need for a chemical improvement, our present study highlights chloroquine as the main drug having the potential for drug repurposing.

A 24-week, multicenter, open-label, randomized study to compare changes in glucose metabolism in patients with schizophrenia receiving treatment with olanzapine, quetiapine, or risperidone

OBJECTIVE

This randomized, 24-week, flexible-dose study compared changes in glucose metabolism in patients with DSM-IV schizophrenia receiving initial exposure to olanzapine, quetiapine, or risperidone.

METHOD

The hypothesized primary endpoint was change (baseline to week 24) in area under the curve (AUC) 0- to 2-hour plasma glucose values during an oral glucose tolerance test (OGTT); primary analysis: olanzapine versus quetiapine. Secondary endpoints included mean change in AUC 0- to 2-hour plasma insulin values, insulin sensitivity index, and fasting lipids. The first patient enrolled on April 29, 2004, and the last patient completed the study on October 24, 2005.

RESULTS

Mean weight change (kg) over 24 weeks was +3.7 (quetiapine), +4.6 (olanzapine), and +3.6 (risperidone). Based on data from 395 patients (quetiapine, N = 115 [mean dose = 607.0 mg/day], olanzapine, N = 146 [mean dose = 15.2 mg/day], and risperidone, N = 134 [mean dose = 5.2 mg/day]), mean change in AUC 0- to 2-hour glucose value (mg/dL x h) at week 24 was significantly lower for quetiapine versus olanzapine (t = 1.98, df = 377, p = .048). Increases in AUC 0- to 2-hour glucose values were statistically significant with olanzapine (+21.9 mg/dL x h, 95% CI = 11.5 to 32.4 mg/dL x h) and risperidone (+18.8 mg/dL x h, 95% CI = 8.1 to 29.4 mg/dL x h), but not quetiapine (+9.1 mg/dL x h, 95% CI = -2.3 to 20.5 mg/dL x h). AUC 0- to 2-hour insulin values increased statistically significantly with olanzapine (+24.5%, 95% CI = 11.5% to 39.0%), but not with quetiapine or risperidone. Reductions in insulin sensitivity index were statistically significant with olanzapine (-19.1%, 95% CI = -27.9% to -9.3%) and risperidone (-15.8%, 95% CI = -25.1% to -5.4%), but not quetiapine. Total cholesterol and low-density lipoprotein levels increased statistically significantly with olanzapine (+21.1 mg/dL, 95% CI = 13.0 to 29.2 mg/dL, and +20.5 mg/dL, 95% CI = 13.8 to 27.1 mg/dL, respectively) and quetiapine (+13.1 mg/dL, 95% CI = 4.3 to 21.9 mg/dL, and +13.3 mg/dL, 95% CI = 6.1 to 20.5 mg/dL, respectively), but not risperidone. Statistically significant increases in triglycerides (+30.9 mg/dL, 95% CI = 10.9 to 51.0 mg/dL), total cholesterol/high-density lipoprotein (HDL) ratio (0.5, 95% CI = 0.2 to 0.8), and triglyceride/HDL ratio (0.3, 95% CI = 0.0 to 0.6) were observed with olanzapine only.

CONCLUSION

The results indicate a significant difference in the change in glucose tolerance during 6 months' treatment with olanzapine versus quetiapine, with significant reductions on olanzapine and risperidone, but not quetiapine; these differential changes were largely explained by changes in insulin sensitivity.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00214578.

Propranolol and blood glucose: simultaneous measurements over a wide range of doses and the effect of propranolol on the glucose tolerance test

No correlation was found between blood glucose and simultaneous measurements of plasma propranolol concentration in patients with schizophrenia, on a daily dose of 80 mg to 1800 mg of propranolol as an adjunct to phenothiazine medication. The Glucose Tolerance Test (GTT) in ten patients on propranolol and phenothiazines did not differ significantly from those of a matched control group on phenothiazine alone. Two patients with mild diabetes showed no significant change in their GTT after stopping propranolol. These observations accord with the view that relatively high doses of propranolol as an adjunct to phenothiazine medication in schizophrenia are safe from the standpoint of glucose metabolism. This does not apply to the insulin dependent diabetic who is in danger of severe hypoglycaemia when glycogenolysis is blocked by propranolol.

Hypothermic action of chlorpromazine in monkeys

1 In the conscious monkey (Macaca cyclopis) intravenous administration of chlorpromazine 0.1-8.0 mg/kg produced a fall of rectal temperature of 0.3 to 3.5 degrees C after a latency of 3.5 to 10.8 minutes. The course of hypothermia lasted from 125 to 600 min or more. 2 Direct injection of chlorpromazine 100-800 mug into the lateral or fourth cerebral ventricle produced a similar fall of 0.3 to 2.0 degrees C but with shorter latency (2 to 3.5 min) and with a duration of 94 to 375 minutes. 3 Two distinct structures in the brain stem, namely, the preoptic anterior hypothalamus (POAH) and medulla oblongata, responded to direct injection of chlorpromazine 200 mug. The sensitivity was slightly higher in the POAH than in the medulla. Structures in between were not sensitive. 4 The results suggest that chlorpromazine works principally through the central nervous system, i.e. the POAH and medulla oblongata, to mediate its hypothermic effect.

Effects of psychotropic drugs on canine cerebral metabolism and circulation related to EEG--diazepam, clomipramine, and chlorpromazine

The effects of diazepam, clomipramine, and chlorpromazine upon cerebral metabolism and blood flow were examined separately in 18 dogs. After the administration of diazepam or clomipramine, cerebral cortical oxygen consumption (CMRO2) decreased significantly by a maximum of 17% and 13% of control within 10 minutes and 15 minutes, and returned to control at 120 minutes and 90 minutes, respectively. Chlorpromazine, however, decreased by a maximum of 10% of control, a level which continued throughout the period of observation. It was observed that reduction in CMRglucose was followed by the reduction in CMRO2 at an interval during the early stages of CMRO2 depression. Diazepam produced a significant decrease in CBF accompanied by reduction in CMRO2, but neither clomipramine nor chlorpromazine had any effect on CBF in spite of reduction in CMRO2. Reduction in CMRO2 both with diazepam and clomipramine was accompanied by slow wave activities of EEG, but with chlorpromazine reduction in CMRO2 was accompanied with less pronounced slow wave activities. It was concluded that the three drugs examined were cerebral metabolic depressants.