The Australian multicentre double-blind comparative study of remoxipride and thioridazine in schizophrenia

In vivo effects of the association of the psychoactive phenotiazine thioridazine on antitumor activity and hind limb paralysis induced by the native polypeptide crotamine

Crotamine is a cationic polypeptide composed by 42 amino acid residues with several pharmacological and biological properties, including the selective ability to enter and kill actively proliferating tumour cells, which led us to propose its use as a theranostic agent for cancer therapy. At the moment, the improvement of crotamine antitumoral efficacy by association with chemotherapeutic adjuvants is envisioned. In the present work, we evaluated the association of crotamine with the antitumoral adjuvant phenotiazine thioridazine (THD). In spite of the clear efficacy of these both compounds as anticancer agents in long-term in vivo treatment of animal model bearing implanted xenograph melanoma tumor, the expected mutual potentiation of the antitumor effects was not observed here. Moreover, this association revealed for the first time the influence of THD on crotamine ability to trigger the hind limb paralysis in mice, and this discovery may represent the first report suggesting the potential involvement of the CNS in the action of this snake polypeptide on the skeletal muscle paralysis, which was classically believed to be essentially limited to a direct action in peripheral tissues as the skeletal muscle. This is also supported by the observed ability of crotamine to potentiate the sedative effects of THD which action was consistently demonstrated to be based on its central action. The better characterization of crotamine properties in CNS may certainly bring important insights for the knowledge needed to pave the way toward the use of this molecule as a theranostic compound in human diseases as cancer.

Cardiotoxicity screening: a review of rapid-throughput in vitro approaches

Cardiac toxicity represents one of the leading causes of drug failure along different stages of drug development. Multiple very successful pharmaceuticals had to be pulled from the market or labeled with strict usage warnings due to adverse cardiac effects. In order to protect clinical trial participants and patients, the International Conference on Harmonization published guidelines to recommend that all new drugs to be tested preclinically for hERG (Kv11.1) channel sensitivity before submitting for regulatory reviews. However, extensive studies have demonstrated that measurement of hERG activity has limitations due to the multiple molecular targets of drug compound through which it may mitigate or abolish a potential arrhythmia, and therefore, a model measuring multiple ion channel effects is likely to be more predictive. Several phenotypic rapid-throughput methods have been developed to predict the potential cardiac toxic compounds in the early stages of drug development using embryonic stem cells- or human induced pluripotent stem cell-derived cardiomyocytes. These rapid-throughput methods include microelectrode array-based field potential assay, impedance-based or Ca(2+) dynamics-based cardiomyocytes contractility assays. This review aims to discuss advantages and limitations of these phenotypic assays for cardiac toxicity assessment.

Thioridazine for schizophrenia

BACKGROUND

Thioridazine is an antipsychotic that can still be used for schizophrenia although it is associated with the cardiac arrhythmia, torsades de pointe.

OBJECTIVES

To review the effects of thioridazine for people with schizophrenia.

SEARCH STRATEGY

For this 2006 update, we searched the Cochrane Schizophrenia Group's Register (June 2006).

SELECTION CRITERIA

We included all randomised clinical trials comparing thioridazine with other treatments for people with schizophrenia or other psychoses.

DATA COLLECTION AND ANALYSIS

We reliably selected, quality rated and extracted data from relevant studies. For dichotomous data, we estimated relative risks (RR), with the 95% confidence intervals (CI). Where possible, we calculated the number needed to treat/harm statistic (NNT/H) on an intention-to-treat basis.

MAIN RESULTS

This review currently includes 42 RCTs with 3498 participants. When thioridazine was compared with placebo (total n=668, 14 RCTs) we found global state outcomes favoured thioridazine (n=105, 3 RCTs, RR 'no change or worse' by 6 months 0.33 CI 0.2 to 0.5, NNT of 2 CI 2 to 3). Thioridazine is sedating (n=324, 3 RCTs, RR 5.37 CI 3.2 to 9.1, NNH 4 CI 2 to 74). Generally, thioridazine did not cause more movement disorders than placebo.Twenty-seven studies (total n=2598) compared thioridazine with typical antipsychotics. We found no significant difference in global state (n=743, 11 RCTs, RR no short-term change or worse 0.98 CI 0.8 to 1.2) and medium-term assessments (n=142, 3 RCTs, RR 0.99, CI 0.6 to 1.6). We found no significant differences in the number of people leaving the study early 'for any reason' (short-term, n=1587, 19 RCTs, RR 1.07 CI 0.9 to 1.3). Extrapyramidal adverse events lower for those allocated to thioridazine (n=1082, 7 RCTs, RR use of antiparkinsonian drugs 0.45 CI 0.4 to 0.6). Thioridazine did seem associated with cardiac adverse effects (n=74, 1 RCT, RR 'any cardiovascular adverse event' 3.17 CI 1.4 to 7.0, NNH 3 CI 2 to 5). Electrocardiogram changes were significantly more frequent in the thioridazine group (n=254, 2 RCTs, RR 2.38, CI 1.6 to 3.6, NNH 4 CI 3 to 10). Six RCTs (total n=344) randomised thioridazine against atypical antipsychotics. Global state rating did not reveal any short-term difference between thioridazine and remoxipride and sulpiride (n=203, RR not improved or worse 1.00 CI 0.8 to 1.3). Limited data did not highlight differences in adverse event profiles.

AUTHORS' CONCLUSIONS

Although there are shortcomings, there appears to be enough consistency over different outcomes and periods to confirm that thioridazine is an antipsychotic of similar efficacy to other commonly used antipsychotics for people with schizophrenia. Its adverse events profile is similar to that of other drugs, but it may have a lower level of extrapyramidal problems and higher level of ECG changes. We would advocate the use of alternative drugs, but if its use in unavoidable, cardiac monitoring is justified.

Risperidone (Risperdal): clinical experience with a new antipsychosis drug

Risperidone (Risperdal) is a benzisoxazole derivative with a high affinity for serotonin 5-HT2 and dopamine D2 receptors, and some affinity for alpha- adrenergic, histamine H1 and dopamine D1 receptors. It has no anticholinergic effects. Early studies demonstrated risperidone to be an effective medication for psychotic symptoms, probably more so than the older neuroleptics for both positive and negative symptoms. At clinically effective doses, risperidone causes no more extrapyramidal side-effects (EPS) than placebo; at higher doses EPS frequency increases in a dose-dependent manner. Since it became available in 1994, extensive experience with the drug supports favourable early impressions of efficacy and tolerability. Minimal sedation, relatively little weight gain and absence of anticholinergic manifestations contribute to the relative tolerability of risperidone as compared to older neuroleptics. However, risperidone is associated with hyperprolactinaemia which can result in amenorrhoea and sexual dysfunction. Compared to older neuroleptics, pharmacoeconomic studies have shown that use of risperidone is associated with reduced hospitalisation and direct cost savings. A recent study found equivalent efficacy between risperidone and clozapine for treatment-resistant patients. Two studies comparing risperidone and olanzapine have yielded positive but conflicting findings. The overall positive experience with risperidone has resulted in the drug being widely recommended as a first line treatment option for psychoses.

New generation antipsychotics versus low-potency conventional antipsychotics: a systematic review and meta-analysis

BACKGROUND

The clearest advantage of new generation, atypical antipsychotics is a reduced risk of extrapyramidal side-effects (EPS), compared with conventional compounds. These findings might have been biased by the use of the high-potency antipsychotic haloperidol as a comparator in most of the trials. We aimed to establish whether the new drugs induce fewer EPS than low-potency conventional antipsychotics.

METHODS

We did a meta-analysis of all randomised controlled trials in which new generation antipsychotics had been compared with low-potency (equivalent or less potent than chlorpromazine) conventional drugs. We included studies that met quality criteria A or B in the Cochrane Collaboration Handbook, and assessed quality with the Jadad scale. The primary outcome of interest was the number of patients who had at least one EPS. We used risk differences and 95% CIs as measures of effect size.

FINDINGS

We identified 31 studies with a total of 2320 participants. Of the new generation drugs, only clozapine was associated with significantly fewer EPS (RD=-0.15, 95% CI -0.26 to -0.4, p=0.008) and higher efficacy than low-potency conventional drugs. Reduced frequency of EPS seen with olanzapine was of borderline significance (-0.15, -0.31 to -0.01, p=0.07). Only one inconclusive trial of amisulpride, quetiapine, and risperidone and no investigations of ziprasidone and sertindole were identified, but some evidence indicates that zotepine and remoxipride do not lead to fewer EPS than low-potency antipsychotics. Mean doses less than 600 mg/day of chlorpromazine or its equivalent had no higher risk of EPS than new generation drugs. As a group, new generation drugs were moderately more efficacious than low-potency antipsychotics, largely irrespective of the comparator doses used.

INTERPRETATION

Optimum doses of low-potency conventional antipsychotics might not induce more EPS than new generation drugs. Potential advantages in efficacy of the new generation drugs should be a factor in clinical treatment decisions to use these rather than conventional drugs.

Pharmacology of the atypical antipsychotic remoxipride, a dopamine D2 receptor antagonist

Remoxipride is a substituted benzamide that acts as a weak but very selective antagonist of dopamine D2 receptors. It was introduced by Astra (Roxiam) at the end of the eighties and was prescribed as an atypical antipsychotic. This article reviews its putative selective effects on mesolimbic versus nigrostriatal dopaminergic systems. In animals, remoxipride has minimal cataleptic effects at doses that block dopamine agonist-induced hyperactivity. These findings are predictive of antipsychotic activity with a low likelihood of extrapyramidal symptoms. Remoxipride also appears to be effective in more recent animal models of schizophrenia, such as latent inhibition or prepulse inhibition. In clinical studies, remoxipride shows a relatively low incidence of extrapyramidal side effects and its effects on prolactin release are short-lasting and generally mild. The clinical efficacy of remoxipride is similar to that of haloperidol or chlorpromazine. Although its clinical use was severely restricted in 1993, due to reports of aplastic anemia in some patients receiving remoxipride, this drug has been found to exhibit relatively high selectivity for dopamine D2 receptors making remoxipride an interesting tool for neurochemical and behavioral studies.

Correlation between neuroleptic binding to sigma(1) and sigma(2) receptors and acute dystonic reactions

Acute dystonic reactions are motor side effects that occur soon after the initiation of neuroleptic treatment. Although earlier studies indicate that these abnormal movements can be induced in animals and humans via activation of sigma receptors, the relative contribution of the different sigma receptor subtypes is unknown. Since sigma(1) and sigma(2) receptor are differentially represented in motor regions of the brain, the affinities of 17 neuroleptics for these sigma receptor subtypes were determined using competition binding studies. The results revealed that most neuroleptics do not exhibit selectivity for either of the sigma receptor subtypes, as reflected by a significant correlation between the affinities of the neuroleptics for sigma(1) vs. sigma(2) receptors. Moreover, when the sigma binding affinities of the neuroleptics were correlated with the tendency of the drugs to produce acute dystonic reactions in humans, there was a significant correlation for both subtypes. Together with earlier studies in animals, the data suggest that neuroleptic-induced motor side effects can be mediated through both sigma(1) and sigma(2) receptors.

Thioridazine for schizophrenia

BACKGROUND

Thioridazine is a piperidine phenothiazine used for the treatment of people with schizophrenia. It has often been considered the drug of choice in the elderly because of reputed lower levels of extrapyramidal adverse events. It may, however, be more likely to cause cognitive adverse events, such as delirium or worsening of memory, and, on rare occasions, thioridazine has caused pigmentary retinopathy.

OBJECTIVES

To examine the effects of thioridazine for those with schizophrenia, and, in particular, elderly people with schizophrenia.

SEARCH STRATEGY

Electronic searches of Biological Abstracts (1980-1999), CINAHL (1982-1999), The Cochrane Library (Issue 3, 1999), The Cochrane Schizophrenia Group's Register (January 1999), EMBASE (1980-1999), MEDLINE (1966-1999), PsycLIT (1974-1999) and Sociofile (1974-1999) were undertaken. References of all identified studies were searched for further trials. Pharmaceutical companies and authors of trials were contacted.

SELECTION CRITERIA

All randomised clinical trials that compared thioridazine to other treatments for people with schizophrenia or other psychoses.

DATA COLLECTION AND ANALYSIS

Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were independently extracted. Data were excluded if loss to follow up was greater than 40%. For homogeneous dichotomous data the Relative Risk (RR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) were calculated on an intention-to-treat basis. For continuous data, weighted mean differences were calculated (WMD). All data were inspected for heterogeneity.

MAIN RESULTS

560 people from 11 studies were randomised to thioridazine or placebo. For change in global state, small, short term studies (three months or less) found no difference between groups (RR 0.66 CI 0.35-1.23, n=100). At six months, however, two small studies (n=65) favoured thioridazine (RR 0.34 CI 0.21-0. 56, NNT 2 CI 1-6). Fourteen percent in the thioridazine group left early compared to 32% of people allocated to placebo (RR 0.43 CI 0. 31-0.61, NNT 6 CI 4-10, n=510). Few differences in terms of adverse effects, between thioridazine and placebo, were apparent. Limited data from trials suggest that thioridazine is not strongly anticholinergic (blurred vision RR 2.01 CI 0.56-7.25, n=224). Thioridazine is not sedating (at three months to one year RR 2.48 CI 0.96-6.4, n=122). No data were presented on retinal changes. Two thousand three hundred ninety-seven patients from 26 studies were randomised to thioridazine versus typical antipsychotics. For the outcome 'no better or worse', those allocated to thioridazine were no better off than people given control typical neuroleptics (RR 0. 97 CI 0.78-1.21, n=771). There were no clear differences between thioridazine and other drugs for the outcome 'Mental state - no better or worse' on the BPRS by three months (RR 1.3 CI 0.8-2.11, n=208). Twenty-one studies (n=1737) had 19% attrition in both groups. Few differences were seen in the lists of adverse effects. As expected from the placebo comparison, thioridazine does not cause more anticholinergic-type symptoms than other drugs. About half of people given thioridazine felt drowsy or sedated but this was no different from other drugs (RR 1.06 CI 0.93-1.2, n=909). Parkinsonism was less common in the thioridazine group in the short term (RR 0.29 CI 0.12-0.7, n=340). One small study (n=40) found no clear differences between thioridazine and clozapine.

REVIEWER'S CONCLUSIONS

Although there are shortcomings and gaps in the data, there appears to be enough consistency over different outcomes and periods to confirm that thioridazine is an antipsychotic of similar efficacy to other commonly used neuroleptics for people with schizophrenia. Its adverse events profile is similar to that of other drugs, but it may have a lower level of extrapyramidal problems. (ABSTRACT TRU

Antipsychotic-induced weight gain: a comprehensive research synthesis

OBJECTIVE

The purpose of this study was to estimate and compare the effects of antipsychotics-both the newer ones and the conventional ones-on body weight.

METHOD

A comprehensive literature search identified 81 English- and non-English-language articles that included data on weight change in antipsychotic-treated patients. For each agent, a meta-analysis and random effects metaregression estimated the weight change after 10 weeks of treatment at a standard dose. A comprehensive narrative review was also conducted on all articles that did not yield quantitative information but did yield important qualitative information.

RESULTS

Placebo was associated with a mean weight reduction of 0.74 kg. Among conventional agents, mean weight change ranged from a reduction of 0.39 kg with molindone to an increase of 3.19 kg with thioridazine. Among newer antipsychotic agents, mean increases were as follows: clozapine, 4.45 kg; olanzapine, 4.15 kg; sertindole, 2.92 kg; risperidone, 2.10 kg; and ziprasidone, 0.04 kg. Insufficient data were available to evaluate quetiapine at 10 weeks.

CONCLUSIONS

Both conventional and newer antipsychotics are associated with weight gain. Among the newer agents, clozapine appears to have the greatest potential to induce weight gain, and ziprasidone the least. The differences among newer agents may affect compliance with medication and health risk.

Body weight gain induced by antipsychotic drugs: mechanisms and management

Long-term administration of typical and atypical antipsychotic drugs (AP) induces excessive weight gain which afflicts up to 50% of patients, impairs health and interferes with treatment compliance. Basic and clinical research has shown that AP may affect body weight through diverse mechanisms. Increased appetite is probably related to the interaction of AP with neuronal receptors to dopamine, serotonin and histamine. Additional metabolic-endocrine disruption of weight regulation may be related to the effects of AP-induced hyperprolactinaemia on gonadal-adrenal steroids and insulin sensitivity. In humans, programmed physical activity, dietary restriction, anorectic agents, and drugs that counteract hyperprolactinaemia have been shown to be successful in a limited number of studies. Two novel strategies could expand the available therapeutic options. First, in preclinical experiments in female rats the estradiol antagonist/agonist drug tamoxifen or estradiol itself have been shown to completely prevent the obesity provoked by the AP sulpiride, and to induce an endocrine-metabolic milieu that seems to counteract AP-induced obesity. Secondly, it has also been shown that oral antihyperglycaemic agents such as metformin may decrease body weight and counteract insulin resistance and hyperinsulinaemia which is correlated with several metabolic abnormalities in obese subjects. Lastly, estradiol replacement, tamoxifen and/or antihyperglycaemic agents are not devoid of significant side-effects, and these drugs have not been tested in obese psychiatric patients. Therefore, further research is needed before their clinical use may be recommended.

Minimizing the non-extrapyramidal side-effects of antipsychotics

Standard neuroleptic medications have been augmented by the introduction of risperidone and clozapine into clinical practice. A great deal of attention has also been focused on efficacy and the lower propensity to extrapyramidal side-effects associated with the new agents. However, antipsychotic medication, both old and new, can cause a range of other adverse effects, some of which are serious, and many of which have the potential greatly to diminish the quality of life of patients who need to take medication in the long term. Of particular significance are postural hypotension, cardiotoxicity, peripheral and central anticholinergic effects, sedation, weight gain, and endocrine and haematological effects. Various antipsychotic compounds differ substantially with regard to propensity to adverse effects. Side-effects can be minimized by optimization of clinical strategies, including choice of appropriate drug, slow titration and dosage reduction. It is also vital to explain carefully to both patients and carers the nature of the side-effects which can be anticipated. The choice of antipsychotic is often determined by evaluation of the potential impact of the various adverse effects on a particular patient. New drugs, such as risperidone, are well tolerated, with fewer side-effects, and should now be considered as a first-line option.

Drug strategies and treatment-resistant schizophrenia

OBJECTIVES

The aims of the paper are to review the notion of treatment resistance in schizophrenia and consider the factors important in determining non-responsiveness to standard neuroleptic treatment, and to review the strategies currently available in the treatment of such patients, including an evaluation of recently-introduced, novel drug treatments.

METHOD

A selective review of the literature relating to treatment resistance was undertaken using medline searches, followed by cross-checking for further articles identified in these references.

RESULTS

The various treatment approaches available are considered, including adjunctive treatment with lithium or carbamazepine. The risks and benefits of high dose antipsychotic treatment are discussed. The possible benefits and side-effects of new treatments, particularly the atypical neuroleptics, are also reviewed.

CONCLUSIONS

The reasons why a proportion of patients with schizophrenia fail to respond to standard neuroleptic treatment are ill-understood. Nevertheless, initial assessment should include identification of any factors that may be related to a patient's poor response, such as poor compliance, substance use or epilepsy. This may help to determine an appropriate treatment strategy. There is a need to be systematic and to ensure that patients be given an adequate trial of each treatment tested in terms of duration and dosage. The available evidence does not support the use of high doses of neuroleptics for the majority of patients. Adjunctive treatments, such as lithium, carbamazepine or benzodiazepines may be beneficial in non-responsive patients, particularly if certain target symptoms are present. Atypical neuroleptics, particularly clozapine, have proved particularly effective in non-responsive patients as well as those sensitive to the motor side-effects of standard drugs. However, the high risk of agranulocytosis with clozapine is a problem; also the drug and the necessary haematological monitoring are expensive. There are hints that some of the other, new, atypical neuroleptics have some benefit in non-responsive patients, but controlled studies are required.