Refractory schizophrenia and atypical antipsychotics

Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia

Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT₂R, D1R, α_2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS.

Augmentation of Antipsychotic Medications with Low-Dose Clozapine in Treatment-Resistant Schizophrenia-Case Reports and Discussion

Treatment resistance in schizophrenia is often encountered in clinical practice, with clozapine usually recommended as the appropriate therapy. However, where clozapine proves ineffective or cannot be tolerated due to side effects, treatment options are limited. In patients within forensic mental health services, residual symptomatology often presents a barrier to discharge and can have lasting effects on prospects for rehabilitation as well as risk to self and others. This paper presents a review of the relevant literature and three cases of a novel approach, utilising clozapine in doses usually considered subtherapeutic, in combination with the primary antipsychotic treatment. In all three patients, it improved clinical efficacy as well as tolerability, resulting in improvement that allowed discharge from the forensic hospital.

Point-of-care measurement of clozapine concentration using a finger-stick blood sample

BACKGROUND

The use of clozapine demands regular monitoring of clozapine plasma concentrations and of white blood cell parameters. The delay between sending blood samples for analysis and receiving the results hinders clinical care. Point-of-care testing (POCT) can provide drug assay results within a few minutes.

AIM

This study aimed to investigate the utility of a novel point-of-care device that can measure clozapine concentrations using capillary blood samples collected via a finger stick.

METHOD

During a five-week period starting in June 2019 eligible patients were asked to provide a finger-stick capillary sample in addition to their usual venous blood sample. Samples were analysed by the novel point-of-care device and by the standard laboratory method. Capillary blood samples were tested by the MyCare™ Insite POCT analyser, and a quantitative measurement of clozapine concentration was provided within six minutes.

RESULTS

A total of 309 patients agreed to measurements by the two methods. Analysis revealed clozapine concentrations in venous blood as determined by the laboratory method ranged from 20 to 1310 ng/mL and by POCT from 7 to 1425 ng/mL. There was a strong positive correlation (R = 0.89) between the results from the venous and the capillary sample methods. The slope of the association between standard assay and MyCare™ Insite was 1.0 with an intercept of -21 ng/mL, indicating minimal bias.

CONCLUSION

Clozapine concentrations can be accurately measured at the point of care using capillary blood samples collected via a finger stick. This approach may be more acceptable than venous sampling to patients and, with almost instant results available, more useful to clinicians.

Clozapine prescription pattern in patients with schizophrenia in Asia: The REAP survey (2016)

Clozapine is an effective antipsychotic medication for treatment resistant schizophrenia and is widely used in Asian countries. This study investigated clozapine prescription patterns and their associated factors in Asian countries and territories based on the database of the Research on Asian Psychotropic prescription study (REAP) conducted in 2016. Demographic and clinical information of 3744 schizophrenia patients in 15 Asian countries and territories was collected with a standardized data collection form. In total, 18.4% of the sample received clozapine, ranging from 2.6% in Japan to 32.3% in Hong Kong. Binary logistic regression analysis revealed that higher antipsychotic dose (OR = 1.002, P < 0.001), less frequent first admission in the sample (OR = 0.6, P < 0.001), more severe negative symptoms (OR = 1.4, P = 0.001) and less first generation antipsychotics (FGAs) (OR = 0.2, P < 0.001) were independently and significantly associated with clozapine prescription. Clozapine is frequently and increasingly prescribed for schizophrenia in Asia, with large variation across countries and territories. Given the diverse prescription patterns of clozapine found in Asian countries/territories, the clinical rationale of clozapine prescription needs careful consideration in Asia with more local input.

Prevalence and awareness of cardiovascular risk factors in patients with schizophrenia: A cross-sectional study in a low cardiovascular disease risk geographical area

Objective

Prevalence of cardiovascular disease is high in schizophrenia. Our aim is to estimate the prevalence of cardiovascular risk factors (CVRF) among schizophrenia patients.

Method

National cross-sectional study in patients diagnosed with schizophrenia under treatment with second generation antipsychotics and admitted to short-stay hospitalisation units.

Results

A sample of 733 consecutively admitted patients was enrolled; the most prevalent CVRFs were smoking 71% (95% CI: 67–74%) and hypercholesterolemia 66% (61–70%) followed by hypertriglyceridemia 26% (26–32%), hypertension 18% (15–21%) and diabetes 5% (4–7%). Metabolic syndrome showed 19% (95% CI: 16–23%) prevalence or, according to updated definitions (Clin Cornerstone 7 [2005] 36–45), 24% (95% CI: 20–28%). The rate of patients within the high-risk range of a 10-year fatal cardiovascular event was 6.5%. CVRFs under routine management were diabetes (60%), hypertension (28%) and, to a lesser extent, dyslipemia (14%). Treatment for CVRFs was associated to gender, men for hypertension OR = 25.34, p < 0.03 and women for diabetes OR = 0.02, p < 0.03.

Conclusion

We found that CVRFs in schizophrenia were prevalent and under-diagnosed, and thus with insufficient therapeutic management.

Clinical Course, Neurobiology and Therapeutic Approaches to Treatment Resistant Schizophrenia. Toward an Integrated View

Despite considerable psychotherapeutic advancement since the discovery of chlorpromazine, almost one third of patients with schizophrenia remain resistant to dopamine-blocking antipsychotics, and continue to be exposed to unwanted and often disabling side effects, but little if any clinical benefit. Even clozapine, the superior antipsychotic treatment, is ineffective in approximately half of these patients. Thus treatment resistant schizophrenia (TRS), continues to present a major therapeutic challenge to psychiatry. The main impediment to finding novel treatments is the lack of understanding of precise molecular mechanisms leading to TRS. Not only has the neurobiology been enigmatic for decades, but accurate and early detection of patients who are at risk of not responding to dopaminergic blockade remains elusive. Fortunately, recent work has started to unravel some of the neurobiological mechanisms underlying treatment resistance, providing long awaited answers, at least to some extent. Here we focus on the scientific advances in the field, from the clinical course of TRS to neurobiology and available treatment options. We specifically emphasize emerging evidence from TRS imaging and genetic literature that implicates dysregulation in several neurotransmitters, particularly dopamine and glutamate, and in addition genetic and neural alterations that concertedly may lead to the formation of TRS. Finally, we integrate available findings into a putative model of TRS, which may provide a platform for future studies in a bid to open the avenues for subsequent development of effective therapeutics.

Accessing Gene Expression in Treatment-Resistant Schizophrenia

Schizophrenia (SCZ) is a mental disorder arising from a complex interaction of genetic and environmental factors. It has been suggested that treatment-resistant schizophrenia (TRS) is a distinct, more severe, and homogenous subgroup of schizophrenia that could present specific biological markers. Our aim was to characterize expression of target genes in blood of TRS patients compared with non-TRS (NTRS) patients and healthy controls (HC). TRS has been defined using failure to respond to two previous antipsychotic trials. We hypothesized that genes involved in neurodevelopment, myelination, neuroplasticity, neurotransmission, and miRNA processing could be involved in treatment resistance; then, we investigated 13 genes related to those processes in 256 subjects, being 94 healthy controls and 162 schizophrenia patients treated with antipsychotics. Of those, 78 were TRS patients and 84 were NTRS patients. Peripheral blood samples were collected from all subjects and RNA was isolated. Gene expression analysis was performed using the TaqMan low-density array (TLDA) technology. To verify the influence of expression quantitative trait loci (eQTLs), we evaluated single-nucleotide polymorphism (SNP) of all genes using data from GTEx Project. SNP genotypes were obtained from HumanOmniExpress BeadChip. We did not detect gene expression differences between TRS and NTRS subjects, indicating candidate genes specific to treatment resistance. We detected an upregulation of CNR1 and UFD1L gene expression in patients (TRS and NTRS groups) when compared to controls, that may be associated with the release of neurotransmitters, which can influence neuronal plasticity, or with a stress response-activating protein degradation. DICER1 and AKT1 expression increased slightly across the groups and could differentiate only the extreme opposite groups, HC and TRS. Both genes act in heterogeneous pathways, such as cell signaling and miRNA processing, and seem to have an increased demand in the TRS group. We did not detect any eQTLs in our sample that could explain differences in mRNA levels, suggesting a possible regulation by other mechanism, not driven by genotypes. Our data strengthen the importance of several biological pathways involved in the schizophrenia refractoriness and severity, adding knowledge to develop more effective treatments in the future.

Valproate as prophylaxis for clozapine-induced seizures: survey of practice

Aims and Method

To evaluate the prescribing of valproate in clozapine-treated individuals who may be at risk of seizure. We collected point-prevalent clinical characteristics and demographics of all in-patients prescribed clozapine in an acute mental health trust. Data were collected from case notes, electronic records and drug charts, and analysed against a set audit standard.

Results

Data were collected for 81 in-patients. Of all deemed to be at risk of seizure (n=37) only 24% were prescribed valproate at a therapeutic plasma level.

Clinical Implications

The majority of patients prescribed clozapine at risk of seizures were not adequately protected from this risk. Clear guidelines are required.

Distinguishing Between Treatment-Resistant and Non-Treatment-Resistant Schizophrenia Using Regional Homogeneity

Background: Patients with treatment-resistant schizophrenia (TRS) and non-treatment-resistant schizophrenia (NTRS) respond to antipsychotic drugs differently. Previous studies demonstrated that patients with TRS or NTRS exhibited abnormal neural activity in different brain regions. Accordingly, in the present study, we tested the hypothesis that a regional homogeneity (ReHo) approach could be used to distinguish between patients with TRS and NTRS. Methods: A total of 17 patients with TRS, 17 patients with NTRS, and 29 healthy controls (HCs) matched in sex, age, and education levels were recruited to undergo resting-state functional magnetic resonance imaging (RS-fMRI). ReHo was used to process the data. ANCOVA followed by post-hoc t-tests, receiver operating characteristic curves (ROC), and correlation analyses were applied for the data analysis. Results: ANCOVA analysis revealed widespread differences in ReHo among the three groups in the occipital, frontal, temporal, and parietal lobes. ROC results indicated that the optimal sensitivity and specificity of the ReHo values in the left postcentral gyrus, left inferior frontal gyrus/triangular part, and right fusiform could differentiate TRS from NTRS, TRS from HCs, and NTRS from HCs were 94.12 and 82.35%, 100 and 86.21%, and 82.35 and 93.10%, respectively. No correlation was found between abnormal ReHo and clinical symptoms in patients with TRS or NTRS. Conclusions: TRS and NTRS shared most brain regions with abnormal neural activity. Abnormal ReHo values in certain brain regions might be applied to differentiate TRS from NTRS, TRS from HC, and NTRS from HC with high sensitivity and specificity.

Blood Pressure and Heart Rate Changes During Clozapine Treatment

People with schizophrenia are 3-4 times more likely to die from cardiovascular disease than the general population. Clozapine (CLZ) is the gold standard of treatment for refractory schizophrenia. It has been associated with tachycardia and recent evidence shows individuals prescribed CLZ may develop blood pressure (BP) elevation and hypertension. The purpose of this study was to examine the effects of CLZ on BP and heart rate (HR). This was a retrospective chart review of patients 18-75 years old with a DSM IV diagnosis of Schizophrenia or Schizoaffective disorder. Primary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR measured 12 weeks before and 24 weeks during CLZ treatment. Eighteen patient records were included in this study. The mean stabilized CLZ dose was 441.7 ± 171.8 mg/day. DBP (t = 1.02, df = 79.5, = 2.00, 0.049) and HR (t = 1.32, df = 355  = -4.61, < 0.0001) were significantly higher after CLZ initiation. A trend was noted for increase in SBP (p = 0.071). 22 % of patients met criteria for hypertension before CLZ and 67 % during CLZ treatment (Chi Square = 6.25, df = 1, p = 0.0124). No significant changes in weight or renal function occured during CLZ treatment. No patients had evidence of cardiomyopathy. The data suggest CLZ may be associated with a rise in BP and HR. The results of this study support previous literature that found an increase in SBP/DBP regardless of CLZ dose, occurring early in treatment. Due to high risk of cardiovascular morbidity and mortality, more work is needed to determine risk factors and understand the mechanism of action that may cause this side effect.

Quantitative exploration of factors influencing psychotic disorder ailments in Nigeria

In this data article, records on demographic data, family problem issues, as well as results of medical tests from five major classes of psychotic disorder namely: bipolar; vascular dementia, minimal brain dysfunction; insomnia; and schizophrenia, were collected on 500 psychotic patients carefully selected from the pool of medical records of Yaba Psychiatric Hospital, Lagos, Nigeria, for the period of 5 years, between January 2010 and December 2014, were examined. X-squared Statistic was used to examine each of psychotic disorders to identify demographic (age, gender, religion, marital status, and occupation) and family issues (loss of parent, history of such ailment in the family (family status), divorce, head injury, and heredity of such ailment (genetic) factors that influence them. A clear description on each of these psychotic disorders (bipolar; vascular dementia, minimal brain dysfunction (MBD), insomnia and Schizophrenia) was considered separately using tables and bar diagrams. Data analysis results are as follows: firstly, 40.2%, of the 500 psychotic patients tested positive to bipolar, 40.6% to insomnia, 75.0% to schizophrenia, 43.6% to MBD and 69.2% to vascular dementia. Secondly, female patients were more prone to all the psychotic indicators than their male counterpart except in MBD. Thirdly, the oldest age group (> 60 years) is more prone to bipolar and insomnia ailments, while the mid age group (30 - 60 years) is prone to schizophrenia and vascular dementia, and the youngest group (< 30 years) is prone to MBD. Lastly, the factors that influence the ailments are listed: bipolar (age, occupation, marital status, divorce, and spiritual consultation); insomnia (age, occupation, marital status, divorce, and spiritual consultation); schizophrenia (age, occupation, religion, marital status, hereditary, and divorce); MBD (gender, age, occupation, and marital status); and vascular dementia (history of the ailment and spiritual consultation). Bipolar and insomnia are influenced by the same set of factors, which implies that any patient having one is most likely to be at risk of having the other.

Clozapine combined with different antipsychotic drugs for treatment-resistant schizophrenia

BACKGROUND

Between 40% and 70% of people with treatment-resistant schizophrenia do not respond to clozapine, despite adequate blood levels. For these people, a number of treatment strategies have emerged, including the prescription of a second anti-psychotic drug in combination with clozapine.

OBJECTIVES

To determine the clinical effects of various clozapine combination strategies with antipsychotic drugs in people with treatment-resistant schizophrenia both in terms of efficacy and tolerability.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Study-Based Register of Trials (to 28 August 2015) and MEDLINE (November 2008). We checked the reference lists of all identified randomised controlled trials (RCT). For the first version of the review, we also contacted pharmaceutical companies to identify further trials.

SELECTION CRITERIA

We included only RCTs recruiting people of both sexes, aged 18 years or more, with a diagnosis of treatment-resistant schizophrenia (or related disorders) and comparing clozapine plus another antipsychotic drug with clozapine plus a different antipsychotic drug.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data, we calculated risk ratios (RRs) and 95% confidence intervals (CI) on an intention-to-treat basis using a random-effects meta-analysis. For continuous data, we calculated mean differences (MD) and 95% CIs. We used GRADE to create 'Summary of findings' tables and assessed risk of bias for included studies.

MAIN RESULTS

We identified two further studies with 169 participants that met our inclusion criteria. This review now includes five studies with 309 participants. The quality of evidence was low, and, due to the high degree of heterogeneity between studies, we were unable to undertake a formal meta-analysis to increase the statistical power.For this update, we specified seven main outcomes of interest: clinical response in mental state (clinically significant response, mean score/change in mental state), clinical response in global state (mean score/change in global state), weight gain, leaving the study early (acceptability of treatment), service utilisation outcomes (hospital days or admissions to hospital) and quality of life.We found some significant differences between clozapine combination strategies for global and mental state (clinically significant response and change), and there were data for leaving the study early and weight gain. We found no data for service utilisation and quality of life. Clozapine plus aripiprazole versus clozapine plus haloperidolThere was no long-term significant difference between aripiprazole and haloperidol combination strategies in change of mental state (1 RCT, n = 105, MD 0.90, 95% CI -4.38 to 6.18, low quality evidence). There were no adverse effect data for weight gain but there was a benefit of aripiprazole for adverse effects measured by the LUNSERS at 12 weeks (1 RCT, n = 105, MD -4.90, 95% CI -8.48 to -1.32) and 24 weeks (1 RCT, n = 105, MD -4.90, 95% CI -8.25 to -1.55), but not 52 weeks (1 RCT, n = 105, MD -4.80, 95% CI -9.79 to 0.19). Similar numbers of participants from each group left the study early (1 RCT, n = 106, RR 1.27, 95% CI 0.72 to 2.22, very low quality evidence). Clozapine plus amisulpride versus clozapine plus quetiapine One study showed a significant benefit of amisulpride over quetiapine in the short term, for both change in global state (Clinical Global Impression (CGI): 1 RCT, n = 50, MD -0.90, 95% CI -1.38 to -0.42, very low quality evidence) and mental state (Brief Psychiatric Rating Scale (BPRS): 1 RCT, n = 50, MD -4.00, 95% CI -5.86 to -2.14, low quality evidence). Similar numbers of participants from each group left the study early (1 RCT, n = 56, RR 0.20, 95% CI 0.02 to 1.60, very low quality evidence) Clozapine plus risperidone versus clozapine plus sulpirideThere was no difference between risperidone and sulpiride for clinically significant response, defined by the study as 20% to 50% reduction in Positive and Negative Syndrome Scale (PANSS) (1 RCT, n = 60, RR 0.82, 95% CI 0.40 to 1.68, very low quality evidence). There were similar equivocal results for weight gain (1 RCT, n = 60, RR 0.40, 95% CI 0.08 to 1.90, very low quality evidence) and mental state (PANSS total: 1 RCT, n = 60, MD -2.28, 95% CI -7.41 to 2.85, very low quality evidence). No-one left the study early. Clozapine plus risperidone versus clozapine plus ziprasidoneThere was no difference between risperidone and ziprasidone for clinically significant response (1 RCT, n = 24, RR 0.80, 95% CI 0.28 to 2.27, very low quality evidence), change in global state CGI-II score (1 RCT, n = 22, MD -0.30, 95% CI -0.82 to 0.22, very low quality evidence), change in PANSS total score (1 RCT, n = 16, MD 1.00, 95% CI -7.91 to 9.91, very low quality evidence) or leaving the study early (1 RCT, n = 24, RR 1.60, 95% CI 0.73 to 3.49, very low quality evidence). Clozapine plus ziprasidone versus clozapine plus quetiapineOne study found, in the medium term, a superior effect for ziprasidone combination compared with quetiapine combination for clinically significant response in mental state (> 50% reduction PANSS: 1 RCT, n = 63, RR 0.54, 95% CI 0.35 to 0.81, low quality evidence), global state (CGI - Severity score: 1 RCT, n = 60, MD -0.70, 95% CI -1.18 to -0.22, low quality evidence) and mental state (PANSS total score: 1 RCT, n = 60, MD -12.30, 95% CI -22.43 to -2.17, low quality evidence). There was no effect for leaving the study early (1 RCT, n = 63, RR 0.52, CI 0.05 to 5.41, very low quality evidence).

AUTHORS' CONCLUSIONS

The reliability of results from this review is limited, evidence is of low or very low quality. Furthermore, due to the limited number of included studies, we were unable to undertake formal meta-analyses. As a consequence, any conclusions drawn from these findings are based on single, small-sized RCTs with high risk of type II error. Properly conducted and adequately powered RCTs are required. Future trialists should seek to measure patient-important outcomes such as quality of life, as well as clinical response and adverse effects.

Comparative study of clozapine versus risperidone in treatment-naive, first-episode schizophrenia: A pilot study

BACKGROUND & OBJECTIVES

Clozapine may be more useful in treatment-naive patients with first-episode schizophrenia for better symptoms control and improving quality of life. The current study was carried out to compare the efficacy and tolerability of clozapine versus risperidone in treatment-naive, first-episode patients of schizophrenia.

METHODS

This was a comparative, open-label, six months prospective study of treatment-naive, first-episode patients with schizophrenia between the age group of 18 and 40 yr diagnosed as per the International Classification of Diseases-10 (ICD-10) criteria. A total of 63 patients were recruited and randomly assigned to clozapine group or risperidone group using computer-generated random number tables. Eight patients were lost to follow up. The dosages of the respective drugs were kept in therapeutic range of 200-600 mg/day and 4-8 mg/day orally for clozapine and risperidone, respectively.

RESULTS

On general psychopathology score, after six months of intervention, clozapine led to 60.32 per cent mean reduction in Positive and Negative Syndrome Scale (PANSS) for Schizophrenia total score while risperidone led to 56.35 per cent mean reduction in PANSS total score, which meant more improvement with clozapine. Clozapine group was found to have significant improvement in quality of life (P = 0.04339). On Glasgow Antipsychotic Side-effect Scale, clozapine was superior to risperidone. The most common side effects observed in clozapine group were oversedation (78.96%) and dizziness (55.23%), and in risperidone group, common side effects were rigidity (62.36%), sedation (38.69%), tremors (65.69%) and menstrual irregularities in 80.25 per cent of female patients.

INTERPRETATION & CONCLUSIONS

The findings of this preliminary study showed clozapine as a better choice than risperidone in terms of efficacy, tolerability and better quality of life in treatment-naive, first-episode schizophrenia. However, further studies need to be done on a larger group of patients to confirm the findings.

Treatment-Resistant Schizophrenia

Although treatment-resistant schizophrenia (TRS) was described 50 years ago and has a gold standard treatment with clozapine based on well-defined criteria, there is still a matter of great interest and controversy. In terms of the underlying mechanisms of the development of TRS, progress has been made for the elucidation of the neurochemical mechanisms. Structural neuroimaging studies have shown that patients with TRS have significant reduction of the prefrontal cortex volume when compared with non- TRS. This article updates and enhances our previous review with new evidence mainly derived from new studies, clinical trials, systematic reviews, and meta-analyses.

Molecular docking based screening of GABA (A) receptor inhibitors from plant derivatives

The present antipsychotic drugs have known to show serious concerns like extra pyramidal side effects therefore, pursuit for novel antipsychotic GABAnergic drugs has lately focused on the folkloric medicine from plant derivatives as better treatment option of schizophrenia. The present study centers to identify potential inhibitors of plant origin for GABA receptor through in silico approaches. Three compound datasets were undertaken in the study. The first set consisted of seven compounds which included Magnolol, Honokiol and other plant derivatives. The second set consisted of 16 derivatives of N-diarylalkenyl-piperidinecarboxylic acid synthesized by Zheng et al., 2006. The third dataset had thirty two compounds which were Magnolol and Honokiol analogues synthesized by Fuchs et al., 2014. All the compounds were docked at the allosteric site of the GABA (A) receptor. The compounds were further tested for ADMET and biological activity. We observed Honokiol and its derivatives demonstrated superior druglike properties than any compound undertaken in the study. Further, compound 61 [2-(4-methoxyphenyl)-4-propylphenol] of dataset three - a synthetic derivative of honokiol had better profile than its parent compound. In a possible attempt to identify compound with even better efficacious compound than 61, virtual screening was performed, 135 compounds akin to compound 61 were retrieved. Interestingly none of the 135 compounds showed better druggable properties than compound 61. Our in silico pharmacological profiling of compounds is in coherence and is complemented by the findings of Fuchs et al, which also revealed compound 61 to be the good potentiator of GABA receptor.

ABBREVIATIONS

GABA (A) R - Gamma Amino Butyric Acid Receptor, subtype A, GPCR - G Protein Coupled Receptor, OPLS - Optimized Potentials for Liquid Simulations, PDB - Protein Data Bank, PLP - Piece wise Linear Potential, T.E.S.T - Toxicity Estimation Software Tool, TCM - Traditional Chinese Medicine.

Does the dopamine hypothesis explain schizophrenia?

The dopamine hypothesis has been the cornerstone in the research and clinical practice of schizophrenia. With the initial emphasis on the role of excessive dopamine, the hypothesis has evolved to a concept of combining prefrontal hypodopaminergia and striatal hyperdopaminergia, and subsequently to the present aberrant salience hypothesis. This article provides a brief overview of the development and evidence of the dopamine hypothesis. It will argue that the current model of aberrant salience explains psychosis in schizophrenia and provides a plausible linkage between the pharmacological and cognitive aspects of the disease. Despite the privileged role of dopamine hypothesis in psychosis, its pathophysiological rather than etiological basis, its limitations in defining symptoms other than psychosis, as well as the evidence of other neurotransmitters such as glutamate and adenosine, prompt us to a wider perspective of the disease. Finally, dopamine does explain the pathophysiology of schizophrenia, but not necessarily the cause per se. Rather, dopamine acts as the common final pathway of a wide variety of predisposing factors, either environmental, genetic, or both, that lead to the disease. Other neurotransmitters, such as glutamate and adenosine, may also collaborate with dopamine to give rise to the entire picture of schizophrenia.

Add-on filgrastim during clozapine rechallenge unsuccessful in preventing agranulocytosis

Granulocyte colony-stimulating factor agents such as filgrastim can be administered in order to reduce the duration of clozapine-induced agranulocytosis. Successful long-term combination treatment with filgrastim and clozapine in patients with previous clozapine-induced agranulocytosis has been described in several cases. We describe a patient with schizophrenia who developed agranulocytosis during treatment with clozapine and who did not respond to other antipsychotics. Add-on treatment with filgrastim during a clozapine rechallenge did not prevent the reoccurrence of agranulocytosis, and clozapine treatment had to be discontinued. Our case suggests that add-on filgrastim is a therapeutic option when clozapine is rechallenged, but physicians should be aware of the potential dangers especially severe clozapine-induced agranulocytosis.

A review of the use of clozapine levels to guide treatment and determine cause of death

OBJECTIVE

To review the literature to examine the use of clozapine levels to (i) guide therapy and prevent toxicity in clinical care and (ii) determine cause of death in post-mortem examination of patients who were treated with clozapine.

METHODS

MEDLINE was searched in December 2010 using the following keywords: 'clozapine levels', 'clozapine and toxicity', 'clozapine and death', 'clozapine and mortality' and 'post-mortem redistribution'. Data was also collected from the 2010 MIMS Annual.

RESULTS

The literature reported significant variation in clozapine levels attained with any given dose, and considerable variability in the clinical response achieved at any given clozapine level. The lowest effective clozapine levels ranged from 250 to 550 µg/L, while the recommended upper limit to prevent toxicity varied from 600 to 2000 µg/L. There was minimal correlation between clozapine levels and side effects, with the exception of sedation, hypotension and seizure activity. The risk of seizures increased with plasma clozapine levels greater than 600 µg/L or rapid upward titration. In addition to prescribed dose, there are many factors that influence plasma clozapine levels. After death, the process of post-mortem drug redistribution resulted in 3.00 to 4.89 times increases in clozapine levels in central blood vessels and 1.5 fold increases in peripheral vessels compared to ante-mortem levels.

CONCLUSIONS

The exact range of clozapine levels that corresponds to toxicity remains unclear. However, levels between 350 µg/L and 1000 µg/L achieved with gradual upward titration are more likely to be effective and less likely to cause toxicity. Ongoing clozapine level monitoring is indicated, especially when (i) prescribing higher doses (> 600 mg/day) of clozapine, (ii) there has been a change in a patient's concomitant pharmacotherapy or cigarette use and (iii) there has been a suboptimal response to treatment. The use of post-mortem clozapine levels to determine clozapine toxicity as a cause of death is unreliable.

Clozapine resistance: augmentation strategies

BACKGROUND

Clozapine (CLZ) is not effective in more than 50% of treatment-resistant schizophrenic patients. In these cases, several pharmacological strategies are used in clinical practice, with different levels of evidence for both safety and efficacy.

OBJECTIVES

In the present paper we critically reviewed literature data regarding the efficacy and safety of adjunctive agents in CLZ-resistant schizophrenics. The following classes of agents were considered: 1) antipsychotics, 2) antidepressants, 3) mood stabilizers, 4) other agents (e.g. fatty acid supplement and glutamatergic agents), 5) electroconvulsive therapy (ECT). For lamotrigine and risperidone sufficient data were available to perform a meta-analysis.

METHODS

A Medline literature search covering a 20-year period was performed. For the meta-analysis, data were entered and analyzed with the Cochrane Collaboration Review Manager Software (RevMan version 5).

RESULTS

62 pertinent studies were identified, including 1556 schizophrenic or schizoaffective patients. Among treatments investigated, there is evidence for CLZ augmentation with 1) amisulpride and aripiprazole, 2) mirtazapine and 3) ethyl eicosapentaenoic acid (E-EPA). Although promising, ECT augmentation needs further validation. The meta-analyses did not support either the use of risperidone or lamotrigine as CLZ adjunct.

CONCLUSION

Overall, there is scarce evidence of efficacy and safety as regards adjunctive strategies for CLZ-resistant patients. However, several limitations do not allow to draw any definitive conclusion; among these we underline the small sample size of clinical trials, the variable definitions of CLZ resistance, the heterogeneity of outcome measures and methodological designs.

Homobivalent ligands of the atypical antipsychotic clozapine: design, synthesis, and pharmacological evaluation

To date all typical and atypical antipsychotics target the dopamine D(2) receptor. Clozapine represents the best-characterized atypical antipsychotic, although it displays only moderate (submicromolar) affinity for the dopamine D(2) receptor. Herein, we present the design, synthesis, and pharmacological evaluation of three series of homobivalent ligands of clozapine, differing in the length and nature of the spacer and the point of attachment to the pharmacophore. Attachment of the spacer at the N4' position of clozapine yielded a series of homobivalent ligands that displayed spacer-length-dependent gains in affinity and activity for the dopamine D(2) receptor. The 16 and 18 atom spacer bivalent ligands were the highlight compounds, displaying marked low nanomolar receptor binding affinity (1.41 and 1.35 nM, respectively) and functional activity (23 and 44 nM), which correspond to significant gains in affinity (75- and 79-fold) and activity (9- and 5-fold) relative to the original pharmacophore, clozapine. As such these ligands represent useful tools with which to investigate dopamine receptor dimerization and the atypical nature of clozapine.

Gabapentin adjunctive to risperidone or olanzapine in partially responsive schizophrenia: an open-label pilot study

BACKGROUND

There is a great need in the treatment of schizophrenia for a drug, or drug combinations, to improve clinical response with fewer serious side effects. The objective of this study was to explore the therapeutic effects and tolerability of the anticonvulsant gabapentin as an adjunctive in the treatment of patients with partially responsive schizophrenia.

METHODS

Ten consenting patients with a confirmed Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision diagnosis of schizophrenia were identified. All patients failed at least one 12-week treatment trial with risperidone or olanzapine. Gabapentin was added to ongoing antipsychotic treatment with olanzapine or risperidone for eight weeks. The primary outcome measure was the Positive and Negative Syndrome Scale (PANSS). Other scales included the Calgary Depression Scale (CDSS) and the Abnormal Involuntary Movement Scale (AIMS). Repeated-measures multivariate analysis of variance was utilized to examine changes in outcome measures over time with adjunctive treatment with gabapentin.

RESULTS

There was a significant drop in the PANSS and CDSS scores at endpoint (week 8). There were no significant differences between the two treatment groups with regard to changes in all outcome measures or in AIMS score. The adjunctive treatments were well tolerated and side effects were transient.

CONCLUSION

Gabapentin could be used successfully as an adjunct to novel antipsychotics in partially responsive schizophrenia. However, large controlled studies are needed to examine the effectiveness of gabapentin in psychotic disorders.

Reboxetine enhances the olanzapine-induced antipsychotic-like effect, cortical dopamine outflow and NMDA receptor-mediated transmission

Preclinical data have shown that addition of the selective norepinephrine transporter (NET) inhibitor reboxetine increases the antipsychotic-like effect of the D(2/3) antagonist raclopride and, in parallel, enhances cortical dopamine output. Subsequent clinical results suggested that adding reboxetine to stable treatments with various antipsychotic drugs (APDs) may improve positive, negative and depressive symptoms in schizophrenia. In this study, we investigated in rats the effects of adding reboxetine to the second-generation APD olanzapine on: (i) antipsychotic efficacy, using the conditioned avoidance response (CAR) test, (ii) extrapyramidal side effect (EPS) liability, using a catalepsy test, (iii) dopamine efflux in the medial prefrontal cortex and the nucleus accumbens, using in vivo microdialysis in freely moving animals and (iv) cortical N-methyl-D-aspartate (NMDA) receptor-mediated transmission, using intracellular electrophysiological recording in vitro. Reboxetine (6 mg/kg) enhanced the suppression of CAR induced by a suboptimal dose (1.25 mg/kg), but not an optimal (2.5 mg/kg) dose of olanzapine without any concomitant catalepsy. Addition of reboxetine to the low dose of olanzapine also markedly increased cortical dopamine outflow and facilitated prefrontal NMDA receptor-mediated transmission. Our data suggest that adjunctive treatment with a NET inhibitor may enhance the therapeutic effect of low-dose olanzapine in schizophrenia without increasing EPS liability and add an antidepressant action, thus in principle allowing for a dose reduction of olanzapine with a concomitant reduction of dose-related side effects, such as EPS and weight gain.

Lipid status, anti-oxidant enzyme defence and haemoglobin content in the blood of long-term clozapine-treated schizophrenic patients

OBJECTIVE

Despite clozapine's unique effectiveness in patients with schizophrenia, a number of adverse effects have been recognised including abnormalities in lipid and glucose metabolisms. A high clozapine level in red blood cells (RBCs) and disturbed anti-oxidant enzyme activities in blood from schizophrenic patients prompted us to investigate lipid status and anti-oxidant enzyme defence in the blood of chronic schizophrenic patients on long-term clozapine therapy.

METHODS

Plasma lipids, RBC anti-oxidant enzyme activities and haemoglobin (Hb) content were measured using established procedures in a group of eighteen chronically-medicated (average 630 days of therapy) schizophrenic patients receiving clozapine (average dose of 295 mg/day) and data were compared with those from a group of eighteen well-matched normal controls.

RESULTS

Significantly higher levels of plasma triglycerides (by 47%, p<0.01) and total cholesterol and phospholipids (by 8% and 11%, respectively p<0.05) in patients were found. CuZn-superoxide dismutase (SOD1) activity was markedly higher (by 35%, p<0.001) while selenium-dependent glutathione peroxidase (GSH-Px1) activity was markedly lower (by 41%, p<0.001) in patients. In addition, metHb and HbA1c levels in patients were significantly higher (by 58% and 25%, respectively p<0.001). SOD1 activity was negatively correlated (p<0.001) to GSH-Px1 activity in patients.

CONCLUSIONS

The findings support the view that ongoing oxidative stress may be a mechanism by which clozapine induces some adverse effects that increase the risk of diabetes and metabolic syndrome. If valid, this would indicate that in parallel with long-term clozapine treatment, schizophrenic patients could be encouraged to make some lifestyle changes to limit the detrimental effects of the medication.

Augmentation of atypical antipsychotics with valproic acid. An open-label study for most difficult patients with schizophrenia

OBJECTIVE

Most difficult inpatients with schizophrenia are in serious needs but obviously underrepresented in clinical trials.

METHODS

Very challenging patients received open-label treatment with atypical antipsychotics concurrently augmented with valproic acid. The primary outcome was the newly developed Functional Assessment for Comprehensive Treatment of Schizophrenia (FACT-Sz). Patients improving more than 20 points were classified as responders.

RESULTS

Mean age and illness duration of 28 participants (22 male) were 42 y.o. and 20 years, respectively. They had spent a half of their life admitted after the onset. The average Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impression-Severity (CGI-S) were very severe at 79 and 6.1, respectively, with the baseline Global Assessment of Functioning (GAF) of as low as 21. As a result of augmentation, there were nine responders, 12 partial responders, and seven non-responders including only two patients who got worse. The main antipsychotics were mostly either risperidone or olanzapine. Mean maximum oral dose and blood level of valproic acid were 1907 mg and 91.7 microg/ml, respectively. Overall significant improvements whilst to an inadequate degree were noted in clinical parameters. Valproate augmentation was generally well tolerated but serious adverse effects included thrombocytopenia, anaemia and sedation/falls.

CONCLUSIONS

While these preliminary results need to be tested against tenacious monotherapy or polypharmacy involving clozapine, augmenting atypical antipsychotics with valproic acid can be useful for very severe schizophrenia.

Current perspectives in the treatment of resistant schizophrenia

This article summarizes the current knowledge base on the diagnosis and management of treatment resistant schizophrenia. While the prevalence of treatment resistant schizophrenia is definition dependent, estimates have ranged from 30% to up to 60%. This article first looks into the various diagnostic criteria of treatment resistant schizophrenia. Then the literature is reviewed about the pharmacotherapeutics of its management. Clozapine emerges to be the gold standard. In addition risperidone and high dose olanzapine also emerge as clinically useful options. Other emerging adjunctive treatment options are equally addressed.

Ziprasidone vs clozapine in schizophrenia patients refractory to multiple antipsychotic treatments: the MOZART study

This 18-week, randomized, flexible-dose, double-blind, double-dummy trial evaluated ziprasidone as an alternative to clozapine in treatment-refractory schizophrenia patients. Patients had a DSM-IV diagnosis of schizophrenia, a history of resistance and/or intolerance to at least three acute cycles with different antipsychotics given at therapeutic doses, PANSS score >or= 80, and CGI-S score >or= 4. Patients were randomized to ziprasidone (80-160 mg/day, n = 73) or clozapine (250-600 mg/day, n = 74). On the primary ITT-LOCF analysis, baseline-to-endpoint decreases in PANSS total scores were similar in the ziprasidone (- 25.0 +/- 22.0, 95% CI - 30.2 to - 19.8) and clozapine (- 24.5 +/- 22.5, 95% CI - 29.7 to - 19.2) groups. A progressive and significant reduction from baseline in PANSS total score was observed from day 11 in both study arms. There were also significant improvements on PANSS subscales, CGI-S, CG-I, CDSS, and GAF, without between-drug differences. The two treatment groups had similar rates of early discontinuations due to AEs. AEs were mostly of similar mild-moderate severity in the two groups. There were also no detrimental effects on prolactin, renal and liver function, hematology, and cardiovascular parameters. However, ziprasidone but not clozapine showed a significant reduction of SAS and AIMS scores. Moreover, when compared with clozapine, ziprasidone also had a more favorable metabolic profile, with significant endpoint differences in weight, fasting glucose, total cholesterol, LDL cholesterol, and triglycerides. In conclusion, this trial indicates that both ziprasidone and clozapine, having comparable efficacy coupled with satisfactory general safety and tolerability, may be regarded as valuable options for the short-term treatment of difficult-to-treat schizophrenia patients with a history of multiple resistance and/or intolerance to antipsychotics. The more favorable metabolic profile of ziprasidone may represent an added value that could guide clinicians, at least in the presence of patients at high risk for metabolic disorders.

Ziprasidone vs clozapine in schizophrenia patients refractory to multiple antipsychotic treatments: the MOZART study

This 18-week, randomized, flexible-dose, double-blind, double-dummy trial evaluated ziprasidone as an alternative to clozapine in treatment-refractory schizophrenia patients. Patients had a DSM-IV diagnosis of schizophrenia, a history of resistance and/or intolerance to at least three acute cycles with different antipsychotics given at therapeutic doses, PANSS score >or=80, and CGI-S score >or=4. Patients were randomized to ziprasidone (80-160 mg/day, n=73) or clozapine (250-600 mg/day, n=74). On the primary ITT-LOCF analysis, baseline-to-endpoint decreases in PANSS total scores were similar in the ziprasidone (-25.0+/-22.0, 95% CI -30.2 to -19.8) and clozapine (-24.5+/-22.5, 95% CI -29.7 to -19.2) groups. A progressive and significant reduction from baseline in PANSS total score was observed from day 11 in both study arms. There were also significant improvements on PANSS subscales, CGI-S, CG-I, CDSS, and GAF, without between-drug differences. The two treatment groups had similar rates of early discontinuations due to AEs. AEs were mostly of similar mild-moderate severity in the two groups. There were also no detrimental effects on prolactin, renal and liver function, hematology, and cardiovascular parameters. However, ziprasidone but not clozapine showed a significant reduction of SAS and AIMS scores. Moreover, when compared with clozapine, ziprasidone also had a more favorable metabolic profile, with significant endpoint differences in weight, fasting glucose, total cholesterol, LDL cholesterol, and triglycerides. In conclusion, this trial indicates that both ziprasidone and clozapine, having comparable efficacy coupled with satisfactory general safety and tolerability, may be regarded as valuable options for the short-term treatment of difficult-to-treat schizophrenia patients with a history of multiple resistance and/or intolerance to antipsychotics. The more favorable metabolic profile of ziprasidone may represent an added value that could guide clinicians, at least in the presence of patients at high risk for metabolic disorders.

Clinical aspects of super-refractory schizophrenia: a 6-month cohort observational study

OBJECTIVE

Approximately 30% of treatment-resistant schizophrenic patients do not fully respond to Clozapine and such patients are termed Clozapine non-responders or super-refractory schizophrenics. The aim of this study was to characterize patients with super-refractory schizophrenia according to demographic and psychopathological variables, as compared with patients with refractory schizophrenia or non-refractory subjects.

METHOD

One hundred two outpatients meeting DSM-IV criteria for schizophrenia were followed-up for 6 months. Subjects were classified into 3 groups: non-refractory (n=25), refractory (n=43) and super-refractory (n=34). Psychopathology was assessed by the Positive and Negative Syndrome Scale, the Schedule for Deficit Syndrome, the Calgary Depression Scale and the Quality of Life Scale. Patients were rated at 2-month intervals.

RESULTS

Higher levels of severity at the disease onset as well as higher severity of positive symptoms were found to be predictive of super-refractoriness.

CONCLUSIONS

The super-refractory schizophrenia patients have psychopathological predictive factors that need studies comparing brain images, genetical features and other clinical comparisons.

Clozapine: Current perspective

The author conducted a review of studies that compared the efficacy, tolerability and indication for the use of clozapine in current perspectives for the treatment of resistant schizophrenia/ partial responders.

Treatment-resistant schizophrenia

This article opens with a brief history of pharmacologic treatment of schizophrenia. It then discusses the definition and treatment of treatment-resistant schizophrenia, with particular attention to clinical, biological and neuroimaging correlates, as well as the best treatment options, including the use of clozapine in patients who meet the definition of treatment-resistant schizophrenia.

Restarting clozapine after neutropenia: evaluating the possibilities and practicalities

Clozapine remains the antipsychotic of choice for refractory schizophrenia despite its propensity for serious blood disorders. When neutropenia or agranulocytosis occur in people taking clozapine, cessation of treatment is mandated and relapse often results. Because such patients are usually unresponsive to other antipsychotics, many clinicians consider restarting clozapine, despite the risks involved. However, the risks of clozapine rechallenge vary according to the cause and nature of the blood dyscrasia. Neutropenia can arise because of factors unrelated or indirectly related to clozapine treatment. These include benign ethnic neutropenia, concomitant drug therapy, co-existing medical conditions and drug interactions. In such cases, clozapine may be restarted if non-clozapine causes of neutropenia are identified and eliminated, although concurrent treatment with lithium (to induce leukocytosis) is sometimes necessary. Close monitoring of the patient is essential because it is rarely possible to completely rule out the contribution of clozapine to the blood dyscrasia and because lithium does not protect against clozapine-related agranulocytosis. In cases of clozapine-induced neutropenia (as distinct from agranulocytosis, which may have a different pathology) rechallenge may also be considered and, again, lithium co-therapy may be required. Where clozapine is clearly the cause of agranulocytosis, rechallenge should not be considered or undertaken unless there are very exceptional circumstances (severe and prolonged relapse following clozapine discontinuation). In these cases, re-exposure to clozapine may rarely be attempted where there are facilities for very close and frequent monitoring. Granulocyte colony-stimulating factor is likely to be required as co-therapy, given the very high likelihood of recurrence. Uncertainty over the likely cause of blood dyscrasia in people taking clozapine, coupled with uncertainty over the mechanism by which clozapine causes both neutropenia and agranulocytosis, makes any attempt to restart clozapine a high-risk venture requiring the utmost caution.

The effects of chronic administration of established and putative antipsychotics on natural prepulse inhibition deficits in Brattleboro rats

We previously reported that vasopressin deficient Brattleboro (BRAT) rats exhibit deficits in prepulse inhibition (PPI) of the startle reflex that are consistent with PPI deficits exhibited by patients with schizophrenia and other neuropsychiatric disorders. Preliminary evidence indicates that this may be the basis of a predictive model for antipsychotic drug efficacy. Here we report the effects of acute and chronic administration of established and putative antipsychotics on these PPI deficits. BRAT rats, compared to their derivative strain, Long Evans rats, exhibited significantly decreased PPI and startle habituation consistent with patients with schizophrenia and other neuropsychiatric disorders. The second generation antipsychotics, risperidone and clozapine as well as a neurotensin agonist (PD149163) increased BRAT rat PPI, whereas saline, the typical antipsychotic, haloperidol, and a vasopressin analog (1-desamino-D-arginine vasopressin) did not. Similar to their effects in humans, chronic administration of antipsychotic drugs produced stronger effects than acute administration. These results further support the BRAT rat as a model of sensorimotor gating deficits with predictive validity for antipsychotics. The model appears to be able to differentiate first generation from second generation antipsychotics, identify putative antipsychotics with novel mechanisms (i.e., peptides) and reasonably model the therapeutic time course of antipsychotic drugs in humans.

D4 Dopamine receptor genes of zebrafish and effects of the antipsychotic clozapine on larval swimming behaviour

Zebrafish, a model developmental genetic organism, is being increasingly used in behavioural studies. We have initiated studies designed to evaluate the response of zebrafish to antipsychotic drugs. This study focuses on characterization of zebrafish D4 dopamine receptors (D4Rs) and the response of larval zebrafish to the atypical antipsychotic clozapine. The D4R is of interest because of its high affinity for clozapine, while interest in clozapine stems from its effectiveness in reducing symptoms in acutely psychotic, treatment-resistant schizophrenic patients. By mining the zebrafish genomic database, we identified three distinct D4R genes, drd4a, drd4b and drd4c, and generated full-length open reading frames encoding each of the three D4Rs by reverse transcription-polymerase chain reaction. Gene mapping studies showed that each D4R gene mapped to a distinct chromosomal location in the zebrafish genome, and each gene exhibited a unique expression profile during embryogenesis. When administered to larval zebrafish, clozapine produced a rapid and profound effect on locomotor activity. The effect of clozapine was dose-dependent, resulted in hypoactivity and was prevented by the D4-selective agonist ABT-724. Our data suggest that the inhibitory effect of clozapine on the locomotor activity of larval zebrafish may be mediated through D4Rs.

Experience with risperidone long-acting injection: results of a naturalistic observation study

Typical antipsychotics are effective in the management of schizophrenia, but are associated with troublesome adverse effects which may lead to treatment discontinuation and relapse. Long-acting depot formulations of these drugs improve patient compliance, but do not reduce the incidence of adverse effects. There is evidence to suggest that newer atypical antipsychotic drugs have a reduced propensity to induce movement disorders and are associated with a modest reduction in relapse rates. The introduction of risperidone long-acting injection (RLAI) provided clinicians with the first long-acting formulation of an atypical antipsychotic. Objective. The aim of this study was to investigate the outcomes of patients from an acute mental health trust who received RLAI during the 18-month period following its licensing in the UK in order to examine measures of clinical effectiveness, and reasons for treatment discontinuation. Methods. Data were collected retrospectively from medical notes. Results. Fifty-nine patients were included in the study, and at the time of data collection 32 (54%) had discontinued treatment. The most common reason for discontinuation was lack of effectiveness, although all of the patients who discontinued due to lack of response were treatment resistant. RLAI appeared to be well tolerated, with only 12% of patients discontinuing due to adverse effects. Thirty-eight percent of the patients treated with RLAI showed a good response as measured by discharge from inpatient setting, and of the 22 outpatients at time of data collection, five had one re-hospitalisation during the study period. Conclusion. This study concludes that RLAI appears to be well tolerated, and shows some effectiveness in the treatment of schizophrenia, but may not be effective for patients who are treatment resistant.

Benefits of combining aripiprazole to clozapine: three case reports

OBJECTIVE

A substantial number of patients treated with clozapine shows insufficient response. The author presents the results of adding aripiprazole in patients resistant to clozapine.

METHOD

Three cases of individuals with psychotic symptoms despite clozapine use and with significant side effects that were treated via this combination are presented. Response was evaluated by clinical assessment.

RESULTS

Good clinical results were obtained in all three patients, with improvement of psychotic symptoms and of some of the side effects of clozapine.

CONCLUSION

The findings from this case series suggest that adjunctive therapy with aripiprazole can be of benefit for treating clozapine resistant schizophrenic patients.

Evaluation of an antipsychotic information sheet for patients

Introduction. The objective of this study was to develop a decision aid that patients and clinicians might use to help the patient in the process of selecting an antipsychotic medication. In addition, we aimed to determine the antipsychotic that patients would choose given the information contained in the leaflet. Method. We designed a questionnaire for patients to appraise the contents of the leaflet, their understanding of the leaflet and the potential impact of the leaflet on compliance and therapeutic relationship between patient and doctor. Results. We recruited 30 stable patients with a diagnosis of a psychotic illness to evaluate the leaflet and to determine patient choice. Over 90% of patients felt that the leaflet improved their knowledge of antipsychotic medication. Seventy-six percent of patients agreed that the leaflet contained the right type and amount of information. Seventy percent of respondents believed the leaflet would improve the trust between them and their doctors, and almost half (47%) stated they were more likely to take their medicine after reading the leaflet. Forty percent of patients would prefer to switch antipsychotic medication, with quetiapine being the most frequently preferred option. Conclusion. The results indicate that, for patients in the stable phase of their illness, the leaflet is a useful tool in selecting an antipsychotic medication and may represent a way forward in improving outcomes in patients with psychotic disorders. A larger study examining outcomes using this tool would establish its clinical utility.

Quetiapine. A review of its use in the management of schizophrenia

Quetiapine (Seroquel), a dibenzothiazepine derivative, is an atypical antipsychotic with demonstrated efficacy in acute schizophrenia. In short-term, randomised, double-blind trials, it was usually more effective than placebo, and was generally effective against both positive and negative symptoms. Overall, quetiapine (up to 750 mg/day) was at least as effective as chlorpromazine (up to 750 mg/day) and had similar efficacy to haloperidol (up to 16 mg/day) in patients with acute schizophrenia in randomised, double-blind trials; it was at least as effective as haloperidol 20 mg/day in patients with schizophrenia unresponsive or partially responsive to previous antipsychotic treatment. Improvements in overall psychopathology and positive and negative symptoms with quetiapine (up to 800 mg/day) were similar to those with risperidone (up to 8 mg/day) or olanzapine (15 mg/day) [interim analysis]. Efficacy was maintained for at least 52 weeks in open-label follow-up studies in adult and elderly patients. Quetiapine improved cognitive function versus haloperidol, and depressive symptoms and hostility/aggression versus placebo. Quetiapine is well tolerated. It is associated with placebo-level incidence of extrapyramidal symptoms (EPS) across its entire dose range, appears to have a low risk for EPS in vulnerable patient groups (e.g. the elderly, adolescents or patients with organic brain disorders) and has a more favourable EPS profile than risperidone. Irrespective of dose, quetiapine, unlike risperidone and amisulpride, does not elevate plasma prolactin levels compared with placebo, and previously elevated levels may even normalise. Quetiapine appears to have minimal short-term effects on bodyweight and a favourable long-term bodyweight profile. Preliminary studies indicate that there is a high level of patient acceptability and satisfaction with quetiapine. In conclusion, quetiapine has shown efficacy against both positive and negative symptoms of schizophrenia, and has benefits in improving cognitive deficits, affective symptoms and aggression/hostility. The beneficial effects of quetiapine have been maintained for at least 52 weeks. Quetiapine was effective and well tolerated in hard-to-treat patients, and may be of particular use in these individuals. It is at least as effective as standard antipsychotics and appears to have similar efficacy to risperidone and olanzapine. The relative risk/benefit profile of quetiapine compared with other atypical antipsychotics requires further research in head-to-head trials, although quetiapine's relatively benign tolerability profile distinguishes it from other commonly used atypical agents, particularly with respect to bodyweight, EPS and plasma prolactin levels. Overall, quetiapine has an excellent risk/benefit profile and is a suitable first-line option for the treatment of schizophrenia.

Reversal of sensorimotor gating deficits in Brattleboro rats by acute administration of clozapine and a neurotensin agonist, but not haloperidol: a potential predictive model for novel antipsychotic effects

Prepulse inhibition (PPI) of acoustic startle is decreased in unmedicated schizophrenia patients and similar deficits can be induced in rats through pharmacological, environmental, or neuroanatomical manipulations. Recently, we reported that Brattleboro (BB) rats, a Long Evans (LE) strain with a single gene mutation, have inherent deficits in PPI homologous to those observed in schizophrenia patients. We also reported that PPI deficits in BB rats could be reversed by chronic but not acute administration of 0.5 mg/kg haloperidol. No other dose or drug was tested in that experiment. In this study, we tested the effects of acute subcutaneous administration of several doses of haloperidol as well as the second-generation antipsychotic, clozapine, and the putative novel antipsychotic, PD149163, a neurotensin mimetic that crosses the blood-brain barrier. Consistent with our previous report, BB rats exhibited PPI deficits compared to LE rats and none of the doses of haloperidol produced a significant effect on this PPI deficit. In contrast, 10 and 15 mg/kg of clozapine and all the doses of PD149163 tested reversed the PPI deficits in BB rats. In addition, haloperidol, but not clozapine or PD149163 produced significant catalepsy in BB rats, supporting the notion that PD149163 has a profile consistent with atypical antipsychotics and providing support for the predictive validity of the PPI results. These results further strengthen the notion that the BB rat is a useful predictive model of antipsychotic efficacy and suggest that this model may differentiate between antipsychotics belonging to different therapeutic categories, for example, first- and second-generation agents.

Pharmacotherapy of first-episode psychosis

Early intervention in psychosis has attracted more attention in the last few years. The treatment of this phase of the disorders requires a specific and adapted approach. The issue of engaging the patient is so critical that it influences not only the choice of medication, but also the context and the way in which it is administered. In the case of a first admission, patients should be observed for 24-48 h without any antipsychotic treatment, in order to clarify the diagnosis and exclude the possibility that symptoms are caused by acute intoxication with illicit substances, for example. The diagnosis is often difficult and unstable. A dimensional, rather than a categorical approach, is usually more likely to be adopted. In recent years, atypical antipsychotics have become the most frequently used first-line treatment. They are less likely to cause secondary negative symptoms, cognitive impairments and dysphoria. They also appear to influence the course of depression and hostility/aggression better than conventional neuroleptics, have possibly mood-stabilising properties and, subjectively, are often better accepted by patients. On the risk side, prevalence of acute extrapyramidal side effects and possibly tardive dyskinesia are lower, compared to the older neuroleptics. Although, the risk for short-term weight gain, cardiovascular, and especially hyperglycaemic complications are somewhat higher for some of these antipsychotics. Finally, the dose should be adapted as it has been shown that patients presenting a first psychotic episode respond to a lower dose of antipsychotic. This article focuses on the pharmacotherapy of first-episode psychosis, on the basis of a computerised and a manual search for articles dealing with antipsychotic treatment of these patients. Findings are discussed and combined in clinical guidelines for first-episode affective and non-affective psychosis, for patients with incomplete recovery or treatment resistance, for cases of emergency and for side effects associated with antipsychotic treatment.

Switching treatment-resistant patients with schizophrenia or schizoaffective disorder to olanzapine: a one-year open-label study with five-year follow-up

OBJECTIVE

To determine whether patients with treatment-resistant schizophrenia or schizoaffective disorder would respond when switched to olanzapine and whether they could maintain their response on this atypical antipsychotic.

RESEARCH DESIGN AND METHODS

In this single-center, observational, 1-year open-label study, a cohort of patients was switched to olanzapine due to failure on previous treatment. The patients were followed up (retrospectively) for an additional 5 years. Patients had schizophrenia or schizoaffective disorder and all but one were treatment-resistant. The starting dose was 10 mg/day, with dosage adjustments based on physician judgment.

MAIN OUTCOME MEASURES

The CGI-S and CGI-I scales were the primary outcome measures. During the observation period, positive and negative symptoms, hospital readmission rates and duration of hospitalization were measured, and treatment-emergent adverse events recorded.

RESULTS

Mean age of patients (n = 25) was 39.7 years; 19 were male, and all were Caucasian. The mean number of antipsychotics used prior to olanzapine was 4.6 with risperidone (76%) being the most common. The mean duration of olanzapine therapy was 8.6 months. The average number of hospital admissions per patient dropped from 1.32 during the year prior to olanzapine therapy to 0.39 after starting olanzapine. Total number of hospital days was 1042 the year before and 258 the year after olanzapine treatment. The mean CGI-S score improved from markedly ill at baseline to borderline/mildly ill at study end. The mean CGI-I score was rated much improved at study end. Few adverse events occurred during the study. Twelve patients remained on olanzapine monotherapy after 5 years of treatment (mean duration of 62 months).

CONCLUSIONS

Olanzapine may be a treatment option for patients who fail to respond to treatment with other antipsychotics. Importantly, this is one of the first reports showing that patients with schizophrenia can be maintained on atypical antipsychotic monotherapy for at least 5 years.

Receptor profile of P88-8991 and P95-12113, metabolites of the novel antipsychotic iloperidone

Iloperidone is a novel atypical antipsychotic compound currently under clinical development for the treatment of psychotic disorders. In radioligand binding studies, iloperidone binds with high affinity to serotonin (5-HT) 5-HT2A and noradrenaline alpha1 and alpha2C receptors [Neuropsychopharmacology (2001) 25, 904-914]. The human metabolism of iloperidone generates two major metabolites, P88-8991 and P95-12113. The aim of this study was to compare the receptor affinity profile of P88-8991 and P95-12113 with that of the parent compound. The receptor affinity profile of P88-8991 is comparable to that of iloperidone. This metabolite binds to the following monoamine receptors (pKi values in nM): serotonin 5-HT2A receptors (9.56), adrenergic alpha1 (8.08) and alpha2C (7.79) receptors, and D2A receptors (7.80). Lower affinity is seen for other dopamine, serotonin, alpha2-adrenergic and histamine H1 receptors. In contrast, P95-12113 shows affinity for 5-HT2A receptors (pKi 8.15; which is 60-fold lower than that of iloperidone), adrenergic alpha1 (7.67), alpha2C (7.32) and alpha2B (7.08) receptors. Given this affinity profile, and the observation that P95-12113 does not readily cross the blood-brain barrier, it is unlikely that this metabolite contributes to the therapeutic effect of iloperidone in patients with schizophrenia. However, the comparable receptor binding profile of P88-8991 indicates that it is likely to contribute to the clinical profile of iloperidone.

Management of treatment resistance in schizophrenia

A systematic approach to the evaluation and characterization of treatment resistance in schizophrenia has become increasingly important since the introduction of the second-generation antipsychotics. The need for accurate evaluation will increase further as other new antipsychotic medications are developed. Patients with schizophrenia may manifest poor response to therapy because of intolerance to medication, poor adherence, inappropriate dosing, as well as true resistance of their illness to antipsychotic drug therapy. Criteria for treatment-resistance are presented to help in standardizing treatment and clinical trials. As clinicians face the decision of when to change or augment antipsychotic medications, a clear understanding of the appropriate length of a treatment trial and which target symptoms respond to antipsychotic therapy is critical for maximizing response in patients with treatment-resistant schizophrenia.