Standard and higher dose of olanzapine in patients with schizophrenia or schizoaffective disorder: a randomized, double-blind, fixed-dose study

Olanzapine Pharmacokinetics: A Clinical Review of Current Insights and Remaining Questions

Olanzapine is one of the most widely used antipsychotics since its initial approval by the US Food and Drug Administration in 1996 and has undergone extensive pharmacokinetic study. Despite being utilized in clinical psychiatry for decades, there remain questions regarding the variety of available formulations, the utility of therapeutic drug monitoring, altered kinetic properties in special populations/medical illnesses, the use of high-dose olanzapine, and drug interactions, among many others. We performed a narrative literature review of olanzapine pharmacokinetics in June 2023 using the US National Library of Medicine's PubMed.gov resource (https://www.ncbi.nlm.nih.gov/pubmed) and Google Scholar. Herein, we review clinically relevant aspects of olanzapine pharmacokinetic data while highlighting knowledge gaps and potential areas of future study.

Comparison between olanzapine and aripiprazole treatment for 104 weeks after hospital discharge in schizophrenia spectrum disorders: a multicenter retrospective cohort study in a real-world setting

RATIONALE

The long-term effectiveness of olanzapine and aripiprazole in real clinical conditions at flexible doses in patients after hospital discharge has not been evaluated yet.

OBJECTIVES

This study was a multicenter retrospective cohort study. Patients with schizophrenia (n = 398) were prescribed olanzapine (n = 303) or aripiprazole (n = 95) at hospital discharge. The continuation of olanzapine or aripiprazole at 26, 52, or 104 weeks after the hospital discharge were compared using a Cox proportional hazards model and adjusted for possible confounders.

RESULTS

The Kaplan-Meier survival curves revealed that the continuation of olanzapine at 26 (P = 0.001) and 52 weeks (P = 0.018) was significantly higher than that of aripiprazole but not at 104 weeks. Olanzapine was better than aripiprazole in efficacy at 26 (hazard ratio: 0.321, 95% confidence interval: 0.159-0.645, P = 0.001), 52 (hazard ratio: 0.405, 95% confidence interval: 0.209-0.786, P = 0.008), and 104 weeks (hazard ratio: 0.438, 95% confidence interval: 0.246-0.780, P = 0.005). Aripiprazole was better than olanzapine in tolerability at 104 weeks (hazard ratio: 4.574, 95% confidence interval: 1.415-14.787, P = 0.011). Rates after two years continuation of olanzapine and aripiprazole were not significantly different in patients with less than five years' duration of illness, but olanzapine was more commonly maintained for more than two years in those patients who had been ill for over five years' due to its greater efficacy.

CONCLUSION

Olanzapine treatment showed better continuation rates at 26 and 52 after hospital discharge than aripiprazole, whereas maintenance with the two antipsychotics did not differ significantly at 104 weeks, due reduced tolerability of long-term olanzapine treatment.

Antipsychotic dose, dopamine D2 receptor occupancy and extrapyramidal side-effects: a systematic review and dose-response meta-analysis

Antipsychotic drugs differ in their propensity to cause extrapyramidal side-effects (EPS), but their dose-effects are unclear. Therefore, we conducted a systematic review and dose-response meta-analysis. We searched multiple electronic databases up to 20.02.2023 for fixed-dose studies investigating 16 second-generation antipsychotics and haloperidol (all formulations and administration routes) in adults with acute exacerbations of schizophrenia. The primary outcome was the number of participants receiving antiparkinsonian medication, and if not available, the number of participants with extrapyramidal side-effects (EPS) and the mean scores of EPS rating scales were used as proxies. The effect-size was odds ratio (ORs) compared with placebo. One-stage random-effects dose-response meta-analyses with restricted cubic splines were conducted to estimate the dose-response curves. We also examined the relationship between dopamine D2 receptor (D2R) occupancy and ORs by estimating occupancies from administrated doses. We included data from 110 studies with 382 dose arms (37193 participants). Most studies were short-term with median duration of 6 weeks (range 3-26 weeks). Almost all antipsychotics were associated with dose-dependent EPS with varied degrees and the maximum ORs ranged from OR = 1.57 95%CI [0.97, 2.56] for aripiprazole to OR = 7.56 95%CI [3.16, 18.08] for haloperidol at 30 mg/d. Exceptions were quetiapine and sertindole with negligible risks across all doses. There was very low quality of findings for cariprazine, iloperidone, and zotepine, and no data for clozapine. The D2R occupancy curves showed that the risk increased substantially when D2R occupancy exceeded 75-85%, except for D2R partial agonists that had smaller ORs albeit high D2R occupancies. In conclusion, we found that the risk of EPS increases with rising doses and differs substantially in magnitude among antipsychotics, yet exceptions were quetiapine and sertindole with negligible risks. Our data provided additional insights into the current D2R therapeutic window for EPS.

High-dose olanzapine in treatment-resistant schizophrenia: a systematic review

Background

Treatment-resistant schizophrenia (TRS) affects approximately 30% of people with schizophrenia. Clozapine is the gold standard treatment for TRS but is not always suitable, with a proportion of individuals intolerant of side effects or unable to engage in necessary blood monitoring. Given the profound impact TRS can have on those affected, alternative pharmacological approaches to care are needed.

Objectives

To review the literature on the efficacy and tolerability of high-dose olanzapine (>20 mg daily) in adults with TRS.

Design

This is a systematic review.

Data Sources and Methods

We searched for eligible trials published prior to April 2022 in PubMed/MEDLINE, Scopus and Google Scholar. Ten studies met the inclusion criteria [five randomised controlled trials (RCTs), one randomised crossover trial and four open label studies]. Data were extracted for predefined primary outcomes (efficacy, tolerability).

Results

Compared with standard treatment, high-dose olanzapine was non-inferior in four RCTs, three of which used clozapine as the comparator. Clozapine was superior to high-dose olanzapine in a double-blind crossover trial. Open-label studies demonstrated tentative evidence in support of high-dose olanzapine use. It was better tolerated than clozapine and chlorpromazine in two respective RCTs, and was generally well tolerated in open-label studies.

Conclusion

This evidence suggests high-dose olanzapine is superior for TRS when compared with other commonly used first- and second-generation antipsychotics, including haloperidol and risperidone. In comparison with clozapine, the data are encouraging for the use of high-dose olanzapine where clozapine use is problematic, but larger, better designed trials are needed to assess the comparative efficacy of both treatments. There is insufficient evidence to consider high-dose olanzapine equivalent to clozapine when clozapine is not contraindicated. Overall, high-dose olanzapine was well tolerated, with no serious side effects.

Registration

This systematic review was preregistered with PROSPERO [CRD42022312817].

Divergence of dose-response with asenapine: a cluster analysis of randomized, double-blind, and placebo control study

BACKGROUND

Differences in psychiatric background and dose-response to asenapine in patients with schizophrenia were examined based on efficacy and safety, using data obtained in a double-blind, placebo-controlled trial.

METHODS

Patients with schizophrenia were classified into three clusters by a cluster analysis based on the Positive and Negative Symptom Scale (PANSS) subscores at baseline, using the data from a 6-week, double-blind, placebo-controlled trial. PANSS Marder factor scores were calculated for each cluster. The efficacy of 10 or 20 mg/day of asenapine on PANSS score was used as the primary endpoint, with the incidence of adverse events evaluated as the secondary endpoint.

RESULTS

A total of 529 asenapine-treated patients were classified into 3 clusters: Cluster-P with the higher scores in positive symptoms, disorganized thoughts, and hostility/excitement, Cluster-N with higher scores in negative symptoms, and Cluster-L with overall lower scores. In Cluster-N and Cluster-L, both 10 and 20 mg/day groups showed significant improvement in PANSS scores, while only the 20 mg/day group showed a significant difference in Cluster-P. Cluster-N and Cluster-L had differences in the incidence of adverse events, but this was not seen in Cluster-P.

CONCLUSIONS

The efficacy and safety of asenapine 10 and 20 mg/day differed between the 3 clusters of patients. This suggests that background information regarding baseline psychiatric symptoms may affect the therapeutic response in patients with schizophrenia.

Antipsychotic-Induced Weight Gain: Dose-Response Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Weight gain is among the most important side-effects of antipsychotics. It is, however, unclear whether it is associated with antipsychotic doses. We aimed to fill this gap with a dose-response meta-analysis.

METHODS

We searched multiple electronic databases (last update search June 2021) for all fixed-dose studies that investigated 16 second-generation antipsychotics and haloperidol in adults with acute exacerbation of schizophrenia or with negative symptoms. We estimated the dose-response curves by conducting random-effects dose-response meta-analyses. We used the restricted cubic spline to model the dose-response relationship. The primary outcome was mean weight gain in kg from baseline to endpoint, the secondary outcome was the number of patients with clinically important weight gain.

FINDINGS

Ninety-seven studies with 333 dose arms (36 326 participants) provided data for meta-analyses. Most studies were short-term with median duration of 6 weeks (range 4 to 26 weeks). In patients with acute exacerbation, amisulpride, aripiprazole, brexpiprazole, cariprazine, haloperidol, lumateperone, and lurasidone produced mild weight gain in comparison to placebo (mean difference at any dose≤1 kg), while more significant weight gain was observed by all other drugs. For most drugs, dose-response curves showed an initial dose-related increase in weight which plateaued at higher doses, while for others there was no plateau and some even had bell-shaped curves, meaning less weight gain to be associated with higher doses.

INTERPRETATION

Second-generation antipsychotics do not only differ in their propensity to produce weight gain, but also in the shapes of their dose-response curves. This information is important for dosing decisions in clinical practice.

Olanzapine-samidorphan combination tablets for the treatment of schizophrenia and bipolar I disorder - what is it, and will it be used?

INTRODUCTION

: Although olanzapine remains one of the most efficacious antipsychotic medications for the treatment of schizophrenia, there are significant tolerability concerns related to its weight and metabolic profile. Olanzapine-samidorphan combination tablets (OLZ/SAM), branded as Lybalvi, is a newly FDA approved formulation aimed at attenuating antipsychotic induced weight gain via modulation of the endogenous opioid system with samidorphan, while retaining the robust antipsychotic efficacy of olanzapine.

AREAS COVERED

: We reviewed the published literature of OLZ/SAM for the management of schizophrenia using the US National Library of Medicine's PubMed.gov resource. Topics covered in this narrative review include the pharmacokinetics, pharmacodynamics, tolerability, and efficacy of OLZ/SAM.

EXPERT OPINION

: OLZ/SAM is an effective and well tolerated pharmacologic option in mitigating olanzapine induced weight gain while retaining olanzapine's efficacy. It has a limited effect on metabolic laboratory parameters and cumulatively tends to limit weight gain rather than promote weight loss. Additional research will be needed to determine its effectiveness compared to alternative strategies to attenuate antipsychotic induced weight gain.

Antipsychotics for negative and positive symptoms of schizophrenia: dose-response meta-analysis of randomized controlled acute phase trials

Determining the optimal antipsychotic target dose in acute phase treatment is of high clinical relevance. The effect of antipsychotics on negative symptoms should be taken into account because patients will often continue on the treatment received in the acute phase. Therefore, we conducted a formal dose-response meta-analysis of negative symptoms and positive symptoms based on a systematic review of fixed-dose randomized controlled trials (RCTs) that examined the effectiveness of antipsychotics for the acute exacerbation of schizophrenia. Forty RCTs included a total of 15,689 patients. The 95% effective doses per day for the 13 antipsychotics included and 3 long acting were mostly different for negative and positive symptoms: amisulpride (481 mg, 690.6 mg); aripiprazole (11.9 mg, 11 mg); asenapine (7.61 mg, 5.66 mg); brexpiprazole (2.1 mg, 4 mg); cariprazine (4 mg, 6.51 mg); haloperidol (6.34 mg, 7.36 mg); lurasidone (58.2 mg, 86.3 mg); olanzapine (15.5 mg, 9.52 mg); olanzapine long-acting injection (15.7 mg, 13.5 mg); paliperidone (7.2 mg, 7 mg); paliperidone long-acting injection (7.5 mg, 5.9 mg); quetiapine instant-release (264.2 mg, 316.5 mg); quetiapine extended-release (774 mg, 707.2 mg); risperidone (7.5 mg, 7.7 mg); risperidone long-acting injection (5.13 mg, 6.7 mg); sertindole (13.5 mg, 16.3 mg); and ziprasidone (71.6 mg, 152.6 mg). The shape of the dose-response curves varied across different drugs with most drugs showing a plateau at higher doses. Most dose-response curves suggested that the near-maximum effective doses could be in the lower-to-medium range of the licensed dose. Additional RCTs are necessary to establish the optimal dose.

The Relationships Between Hyperprolactinemia, Metabolic Disturbance, and Sexual Dysfunction in Patients With Schizophrenia Under Olanzapine Treatment

The aim of the study was to assess the relationship between prolactin levels and sexual dysfunction in patients with schizophrenia who use olanzapine medication. The potential risk factors of hyperprolactinemia and sexual dysfunction were also investigated. Patients with schizophrenia undergoing olanzapine monotherapy were invited to participate in this cross-sectional study. The Arizona Sexual Experiences Scale (ASEX) and the Positive and Negative Syndrome Scale were used to evaluate subjective sexual dysfunction and psychopathology, respectively. Levels of prolactin and metabolic parameters were also measured. In total, 279 participants with schizophrenia were recruited. The overall incidences of hyperprolactinemia, sexual dysfunction, and metabolic syndrome were 51.6, 53.8, and 43.7%, respectively. Higher ASEX scores, higher insulin levels, female sex, and younger age were associated with hyperprolactinemia. Prolactin level was significantly correlated with ASEX score. Elevated prolactin levels, concomitant antidepressant, increased insulin resistance, longer illness duration, and female sex were associated with sexual dysfunction. Female participants recorded higher levels of sexual dysfunction than their male counterparts did, whereas male participants had comparatively lower prolactin levels and lower rates of spousal partnership. Hyperprolactinemia, metabolic syndrome, and sexual dysfunction are prevalent in patients with schizophrenia treated with olanzapine. Clinicians should maintain awareness of these problems and monitor them regularly with their patients.

The Impact of Smoking, Sex, Infection, and Comedication Administration on Oral Olanzapine: A Population Pharmacokinetic Model in Chinese Psychiatric Patients

BACKGROUND AND OBJECTIVE: Prior olanzapine population pharmacokinetic (PPK) models have focused on the effects of sex and smoking on olanzapine clearance. This PPK model in Chinese adult psychiatric patients also investigated the influence of comedications and co-occurrence of infections on olanzapine clearance, and explored how to personalize oral olanzapine dosage in the clinical setting.

METHODS

A total of 1546 serum concentrations from 354 patients were collected in this study. A one-compartment model with first-order absorption was employed to develop the PPK model using a nonlinear mixed-effects modeling approach. Covariates included demographic parameters, co-occurrence of infection and concomitant medications (including dangguilonghui tablets, a Chinese herbal medicine for constipation). Bootstrap validation (1000 runs) and external validation of 50 patients were employed to evaluate the final model. Simulations were performed to explore the personalization of olanzapine dosing after stratification by sex, smoking, and comedication with valproate.

RESULTS

Typical estimates for the absorption rate constant (K_a), apparent clearance (CL/F), and apparent distribution volume (V/F) were 0.30 h^-1, 12.88 L/h, and 754.41 L, respectively. Olanzapine clearance was increased by the following variables: 1.23-fold by male sex, 1.23-fold by smoking, 1.23-fold by comedication with valproate, 1.16-fold by sertraline, and 2.01-fold by dangguilonghui tablets. Olanzapine clearance was decreased by the following variables: 0.75-fold by co-occurrence of infection, 0.70-fold by fluvoxamine, and 0.78-fold by perphenazine. The model evaluation indicated that the final model's performance was good, stable, and precise.

CONCLUSION

This study contributes to the personalization of oral olanzapine dosing, but further studies should be performed to verify the effects of infection and comedications, including valproate and dangguilonghui.

Specific Anti-hostility Effects of Atypical Antipsychotics in Persons with Schizophrenia: From Clozapine to Cariprazine

LEARNING OBJECTIVE

After participating in this activity, learners should be better able to:• Evaluate the anti-hostility effects of available atypical antipsychotic agents.

ABSTRACT

In addition to hallucinations and delusions, persons with schizophrenia may exhibit hostility. In clinical trials of antipsychotics, hostility is routinely measured as part of rating scales such as the Brief Psychiatric Rating Scale or Positive and Negative Syndrome Scale. The availability of the atypical antipsychotic clozapine in 1989 led to the observation that it is possible to have a treatment effect on hostility that is independent of the treatment effect on hallucinations or delusions, and independent of general sedative effects. The data supporting this notion of a specific anti-hostility effect are the most robust for clozapine as the data include specifically designed randomized, controlled clinical trials. A specific anti-hostility effect is also observable to various degrees with most of the other atypical antipsychotics, as evidenced in post hoc analyses of clinical trials originally conducted for regulatory purposes, supplemented by post hoc analyses of large effectiveness trials. The generalizability of these studies, however, may be limited. Participants in these trials were not selected for aggressive and hostile behavior. Some of the studies also excluded patients with substance use disorders. The latter is particularly important because alcohol and substance use are well known to increase risk for hostility and aggression. Nevertheless, the repeated demonstrations of the specificity of an anti-hostility effect (in terms of statistical independence of effects on other positive symptoms and of sedation) are of potential clinical importance.

Dose-Response Meta-Analysis of Antipsychotic Drugs for Acute Schizophrenia

OBJECTIVE

The dose-response relationships of antipsychotic drugs for schizophrenia are not well defined, but such information would be important for decision making by clinicians. The authors sought to fill this gap by conducting dose-response meta-analyses.

METHODS

A search of multiple electronic databases (through November 2018) was conducted for all placebo-controlled dose-finding studies for 20 second-generation antipsychotic drugs and haloperidol (oral and long-acting injectable, LAI) in people with acute schizophrenia symptoms. Dose-response curves were constructed with random-effects dose-response meta-analyses and a spline model. The outcome measure was total score reduction from baseline on the Positive and Negative Syndrome Scale or the Brief Psychiatric Rating Scale. The authors identified 95% effective doses, explored whether higher or lower doses than the currently licensed ones might be more appropriate, and derived dose equivalencies from the 95% effective doses.

RESULTS

Sixty-eight studies met the inclusion criteria. The 95% effective doses and the doses equivalent to 1 mg of oral risperidone, respectively, were as follows: amisulpride for patients with positive symptoms, 537 mg/day and 85.8 mg; aripiprazole, 11.5 mg/day and 1.8 mg; aripiprazole LAI (lauroxil), 463 mg every 4 weeks and 264 mg; asenapine, 15.0 mg/day and 2.4 mg; brexpiprazole, 3.36 mg/day and 0.54 mg; haloperidol, 6.3 mg/day and 1.01 mg; iloperidone, 20.13 mg/day and 3.2 mg; lurasidone, 147 mg/day and 23.5 mg; olanzapine, 15.2 mg/day and 2.4 mg; olanzapine LAI, 277 mg every 2 weeks and 3.2 mg; paliperidone, 13.4 mg/day and 2.1 mg; paliperidone LAI, 120 mg every 4 weeks and 1.53 mg; quetiapine, 482 mg/day and 77 mg; risperidone, 6.3 mg/day and 1 mg; risperidone LAI, 36.6 mg every 2 weeks and 0.42 mg; sertindole, 22.5 mg/day and 3.6 mg; and ziprasidone, 186 mg/day and 30 mg. For amisulpride and olanzapine, specific data for patients with predominant negative symptoms were available. The authors have made available on their web site a spreadsheet with this method and other updated methods that can be used to estimate dose equivalencies in practice.

CONCLUSIONS

In chronic schizophrenia patients with acute exacerbations, doses higher than the identified 95% effective doses may on average not provide more efficacy. For some drugs, higher than currently licensed doses might be tested in further trials, because their dose-response curves did not plateau.

A randomized double-blind controlled trial to assess the benefits of amisulpride and olanzapine combination treatment versus each monotherapy in acutely ill schizophrenia patients (COMBINE): methods and design

This report presents the rationale and design of a multi-center clinical trial that examines the efficacy and safety of antipsychotic combination treatment in acutely ill schizophrenia patients compared to antipsychotic monotherapy. Antipsychotic combination treatment is common in clinical practice worldwide, despite clinical guidelines generally not recommending such practice due to lacking evidence for its efficacy and safety. Olanzapine has a related chemical structure and comparable receptor-binding profile as clozapine, which demonstrated superior efficacy in combination studies, but has a more unfavorable side-effect profile compared to olanzapine. Amisulpride and olanzapine have shown promising therapeutic efficacy in meta-analyses in monotherapy for people with schizophrenia. Combining amisulpride and olanzapine, complementary receptor-binding properties may enhance efficacy and possibly reduce (or at least not augment) side effects due to the different receptor profiles and metabolization pathways. Accordingly, we hypothesize that patients treated with amisulpride plus olanzapine show greater improvement on the Positive and Negative Syndrome Scale total score after 8 weeks versus either monotherapy. A randomized, double-blind controlled trial is performed at 16 German centers comparing flexibly dosed monotherapy of oral amisulpride (400-800 mg/day), and olanzapine (10-20 mg/day) and amisulpride-olanzapine co-treatment. Sample size was calculated to be n = 101 per treatment arm, assuming an effect size of 0.500 and a two-sided alpha = 0.025 and beta = 0.90. Recruitment for this trial started in June 2012. Until December 2018, 328 patients have been randomized. Trial conduct has been extended to reach the projected sample size. Publication of the study results is expected in 2019 informing an evidence-based recommendation regarding specific antipsychotic combination treatment.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: Updated recommendations from the British Association for Psychopharmacology

These updated guidelines from the British Association for Psychopharmacology replace the original version published in 2011. They address the scope and targets of pharmacological treatment for schizophrenia. A consensus meeting was held in 2017, involving experts in schizophrenia and its treatment. They were asked to review key areas and consider the strength of the evidence on the risk-benefit balance of pharmacological interventions and the clinical implications, with an emphasis on meta-analyses, systematic reviews and randomised controlled trials where available, plus updates on current clinical practice. The guidelines cover the pharmacological management and treatment of schizophrenia across the various stages of the illness, including first-episode, relapse prevention, and illness that has proved refractory to standard treatment. It is hoped that the practice recommendations presented will support clinical decision making for practitioners, serve as a source of information for patients and carers, and inform quality improvement.

A commentary on the efficacy of olanzapine for the treatment of schizophrenia: the past, present, and future

Olanzapine is a second-generation atypical antipsychotic with proven efficacy for the treatment of schizophrenia. Approved in 1996, olanzapine is one of the most studied antipsychotics, resulting in a considerable amount of clinical data across diverse patient populations. Despite the fact that olanzapine is associated with a known risk of metabolic side effects, including weight gain, many clinicians continue to prescribe olanzapine for the treatment of schizophrenia with the expectation of additional therapeutic antipsychotic efficacy relative to other first-line atypical antipsychotics. The goal of this narrative is to revisit the role of oral olanzapine in the management of patients with schizophrenia, including those with recently diagnosed schizophrenia ("first-episode"), those with an established schizophrenia diagnosis who experience acute exacerbations, those receiving long-term antipsychotic treatment as a maintenance intervention, and those with suboptimal response to antipsychotic treatment, including treatment resistance. Collectively, data from published literature support the favorable efficacy of olanzapine compared with other first- and second-generation antipsychotics, including lower rates of treatment discontinuation and clinically meaningful improvements in the symptoms of schizophrenia. The development of antipsychotic medications with the favorable efficacy of olanzapine, but with reduced weight gain, could address a major unmet need in the treatment of schizophrenia.

Resistance is not futile: treatment-refractory schizophrenia - overview, evaluation and treatment

INTRODUCTION

Schizophrenia is a debilitating condition with three main symptom domains: positive, negative, and cognitive. Approximately one-third of persons with schizophrenia will fail to respond to treatment. Growing evidence suggests that treatment-resistant (refractory) schizophrenia (TRS) may be a distinct condition from treatment-respondent schizophrenia. There is limited evidence on effective treatments for TRS, and a lack of standardized diagnostic criteria for TRS has hampered research. Areas covered: A literature search was conducted using Pubmed.gov and the EMBASE literature database. The authors discuss the pragmatic definitions of TRS and review treatments consisting of antipsychotic monotherapy and augmentation strategies. Expert opinion: Currently available first-line antipsychotic medications are generally effective at treating the positive symptoms of schizophrenia, leaving residual negative and cognitive symptoms. Before diagnosing TRS, rule out any pharmacodynamic or pharmacokinetic failures. Most evidence supports clozapine as having the most efficacy for TRS. If clozapine is used, it should be optimized, and serum levels should be at least 350-420 ng/ml. If clozapine is unable to be tolerated, some evidence suggests olanzapine at dosages up to 40mg/day can be useful. Augmentation strategies have weak evidence. Tailoring treatment to the specific domain is the preferred approach, and the use of a structured assessment/outcome measure is encouraged.

Integrating rare genetic variants into pharmacogenetic drug response predictions

BACKGROUND

Variability in genes implicated in drug pharmacokinetics or drug response can modulate treatment efficacy or predispose to adverse drug reactions. Besides common genetic polymorphisms, recent sequencing projects revealed a plethora of rare genetic variants in genes encoding proteins involved in drug metabolism, transport, and response.

RESULTS

To understand the global importance of rare pharmacogenetic gene variants, we mapped the variability in 208 pharmacogenes by analyzing exome sequencing data from 60,706 unrelated individuals and estimated the importance of rare and common genetic variants using a computational prediction framework optimized for pharmacogenetic assessments. Our analyses reveal that rare pharmacogenetic variants were strongly enriched in mutations predicted to cause functional alterations. For more than half of the pharmacogenes, rare variants account for the entire genetic variability. Each individual harbored on average a total of 40.6 putatively functional variants, rare variants accounting for 10.8% of these. Overall, the contribution of rare variants was found to be highly gene- and drug-specific. Using warfarin, simvastatin, voriconazole, olanzapine, and irinotecan as examples, we conclude that rare genetic variants likely account for a substantial part of the unexplained inter-individual differences in drug metabolism phenotypes.

CONCLUSIONS

Combined, our data reveal high gene and drug specificity in the contributions of rare variants. We provide a proof-of-concept on how this information can be utilized to pinpoint genes for which sequencing-based genotyping can add important information to predict drug response, which provides useful information for the design of clinical trials in drug development and the personalization of pharmacological treatment.

Antipsychotic polypharmacy – confusion reigns

Polypharmacy is usually employed where single drugs are considered insufficiently effective. Some polypharmacy is rational and evidence based, some neither. Antipsychotic polypharmacy remains stubbornly widespread despite condemnation of the practice by numerous bodies. The practice could not be said to be evidence based. Its persistence probably stems from a well-meaning desire to improve response and from confusion about the mechanism of action of antipsychotics. In particular, the concept that more antipsychotic(s) must always be, or might be, ‘better’ is virtually groundless. Nonetheless, some specific antipsychotic polypharmacy regimens have shown particular benefits on adverse effect profiles. Targeted, evidence-based polypharmacy may be the way forward.

[Positive changes in the severity of residual psychotic symptoms in schizophrenic patients switched to treatment with risperidone]

AIM

To evaluate the effect of changing therapy from typical antipsychotics to the atypical antipsychotic risperidone in the treatment of difficult-to-treat residual psychotic symptoms.

MATERIAL AND METHODS

The study included 15 patients, 8 men and 7 women, mean age 49.1±10.25 years, diagnosed with paranoid schizophrenia, partial remission (ICD-10 F20.04). At the beginning all participants received regular maintenance antipsychotic therapy with typical antipsychotics. The patient assessment with the PANSS, CGI scale and GAF scale was performed at the beginning (before the change of antipsychotics to risperidone) and in the end of the study. The primary efficacy endpoint was a reduction in scores on the PANSS items P1 'delusions' and P3 'hallucinatory behavior' to 1 (no such symptom) or 2 (minimal residual symptom). Secondary criteria were positive changes in the severity of other psychopathological symptoms and an increase in the social functioning level. The average dose of risperidone was 4.62±1.35 mg. The duration of treatment was 2 month.

RESULTS

After switching from typical antipsychotics to risperidone and two months monotherapy, there were significant positive changes in the total PANSS score as well as in positive subscale score and CGI-S score. The small, but statistically significant, changes were detected in the overall functioning of the patients (the increase in the GAF score). The dynamics of residual psychotic symptoms was unequal: the severity of hallucinatory symptoms decreased significantly while the delusional symptoms remained unchanged.

CONCLUSION

The authors suggest that excessive dopaminergic blockade might play a significant role in the pathogenesis of residual symptoms. This fact may explain the positive effect of treatment in the cases with the less degree of dopaminergic blockade. If it is true, the treatment strategy in the maintenance phase should not be a direct continuation of acute phase therapy and switching to other drugs and changing of the dose are needed.

Optimal Dosing of Risperidone and Olanzapine in the Maintenance Treatment for Patients With Schizophrenia and Related Psychotic Disorders: A Retrospective Multicenter Study

OBJECTIVES

This study aims to determine the optimal tolerability dose ranges of risperidone (RIS) and olanzapine (OLZ) administered during schizophrenia maintenance phase.

METHODS

Two-year continuation rates of prescription at discharge were examined using a retrospective cohort study method. Adult patients with schizophrenia and related psychotic disorders, receiving antipsychotic monotherapy with RIS or OLZ at discharge, were included. The primary outcome measures were the time to treatment discontinuation and 2-year continuation rates at 4 modal dose ranges of each drug. We estimated the optimal tolerability dose ranges by comparing the continuation rates at various modal doses.

RESULTS

Of 648 patients, 344 received RIS and 304 received OLZ. The RIS 2-year continuation rates at 4 daily modal dose ranges were significantly different (0.5-2.5 mg: 46.0%, 3.0-5.0 mg: 40.0%, 5.5-7.5 mg: 30.0%, and 8.0-10.0 mg: 28.0%), with the difference favoring RIS at lower doses (0.5-5.0 mg) more than higher doses (5.5-10.0 mg). In contrast, there were no significant differences among OLZ 4 modal dose ranges (2.5-7.5 mg: 49.1%, 10.0-15.0 mg: 42.6%, 17.5-22.5 mg: 40.9%, and 25.0-30.0 mg: 39.0%). The time to treatment discontinuation significantly favored OLZ over RIS. However, it did not significantly differ between RIS and OLZ at lower doses.

CONCLUSIONS

It is suggested that the optimal tolerability dose range during maintenance treatment is 0.5 to 5.0 mg/d for RIS and 2.5 to 30 mg/d for OLZ, and that RIS at lower doses is comparable with OLZ at lower doses.

5-HT6 Receptor Antagonist as an Adjunct Treatment Targeting Residual Symptoms in Patients With Schizophrenia: Unexpected Sex-Related Effects (Double-Blind Placebo-Controlled Trial)

BACKGROUND

Treating patients who experience residual psychotic symptoms during remission of schizophrenia remains one of the most challenging problems. The mechanisms underlying these symptoms differ from those of acute hallucinations and delusions. 5-HT6 receptor antagonists have been considered promising agents in treatment of residual psychotic symptoms and cognitive dysfunction. The aim of the study was to assess the efficacy of a selective 5-HT6 inhibitor Avisetron in the reduction of residual psychotic symptoms in patients with schizophrenia on stable antipsychotic therapy.

METHODS

Eighty clinically stable outpatient subjects with schizophrenia with residual psychotic symptoms were randomized in a double-blind manner to 6 weeks of Avisetron or placebo at 1:1 ratio. Subjects received 8 mg of Avisetron or placebo on top their stable antipsychotic treatment. Standard clinical scales and cognitive tests were used for endpoint assessment. The primary efficacy endpoint was the mean reduction of total Positive and Negative Syndrome Scale score after 6 weeks of treatment.

RESULTS

No significant differences in the primary and secondary endpoints were found between the groups. However, based on the subgroup analysis, the significant improvement of total Positive and Negative Syndrome Scale score and residual psychotic symptoms was observed in female patients.

CONCLUSIONS

It was a negative study with unexpected benefits of the drug only in females. We hypothesized that the role of patients' sex can impact the treatment response to serotonergic drugs in general. We suggest a possible synergistic interaction between estrogen and Avisetron by means of modulating the effect of estrogens on the serotonergic system. Future studies targeting the sex-related effects of serotonergic drugs are warranted.

Antipsychotic Prescribing Patterns in First-episode Schizophrenia: A Five-year Comparison

OBJECTIVE

Early treatment choice is critical in first-episode schizophrenia-spectrum disorders. The purpose of this study was to describe prescribing trends of antipsychotics use in patients with first-episode schizophrenia in 2005 and 2010, respectively.

METHODS

We reviewed the medical records of newly treated patients with schizophrenia from a university psychiatric hospital in 2005 (n=47) and 2010 (n=52). We defined patients as receiving a high antipsychotic dose if their ratio of prescribed daily dose (PDD) to defined daily dose (DDD) was greater than 1.5.

RESULTS

The rates of high-dose antipsychotic prescription were 61.7% and 53.8% in 2005 and 2010, respectively. The rates of antipsychotic polypharmacy were 34.6% in 2005 and 34.0% in 2010. The most common first-prescribed antipsychotics were (in descending order of prescription frequency) olanzapine, risperidone, aripiprazole, and haloperidol in 2005 and risperidone, quetiapine, paliperidone, and olanzapine in 2010. High-dose antipsychotics were significantly associated with antipsychotic polypharmacy (odds ratio=23.97; p<0.01). More individuals were treated with mood stabilizers in 2010 than in 2005 (p=0.003).

CONCLUSION

The practice of prescribing high-dose antipsychotics and associated antipsychotic polypharmacy were common even for initial treatment of first-episode schizophrenia in 2005 and 2010. In 2010, the list of the most common first-prescribed antipsychotics changed, and the use of mood stabilizers increased in non-affective schizophrenia.

Practical pharmacotherapy for acute schizophrenia patients

Well-organized clinical guidelines of pharmacotherapy for schizophrenia are not necessarily applicable to emergency and acute-phase situations. Thus, practical pharmacotherapy for acute schizophrenia patients should be based on data from real clinical practice and be independent of pharmaceutical companies. This study investigated the current guidelines being used to determine the initially preferred antipsychotics, durations required before an antipsychotic is viewed as being ineffective, and the strategies utilized for early non-responders that include switching, high dose, and augmentation. In patients who develop side-effects to the preferred antipsychotic drug, continued use may depend on the specific characteristics of the side-effects. For acute-phase patients, antipsychotics with high efficacy and effectiveness may be chosen based on meta-analysis findings for not only double-blinded but also rater-blinded randomized controlled trials. Many previous studies have reported being able to make an early prediction at 2 weeks regarding the later response. These predictions were supported by the findings of a recent meta-analysis of 34 studies that examined 9975 participants. In early non-responders to the initial antipsychotic, the effectiveness of the switching strategy appears to depend on the initial antipsychotic administered and the antipsychotic the patient is subsequently switched to. Furthermore, the effectiveness of the strategy between switching and augmentation might also depend on the initial antipsychotic administered. The current findings might serve as the basis for the use of dosing above the licensed range versus continuing the use of conventional dosing in non-responders, provided there is close monitoring of the side-effects. Further research is required before any modifications of routine practices are undertaken regarding the direction of new potential treatments.

Treatment of early non-response in patients with schizophrenia: assessing the efficacy of antipsychotic dose escalation

BACKGROUND

Early non-response to antipsychotic treatment in patients with schizophrenia has been shown in multiple studies to predict poor response at short-term trial endpoint. Therefore, strategies to address the challenge of non-improvement early in the course of treatment are needed. A novel trial design was developed to assess the potential utility of antipsychotic dose escalation in patients with an inadequate initial treatment response. This design was embedded in a study intended to assess the efficacy of low dose lurasidone in patients with schizophrenia. The purpose of this report is to describe the background, rationale and design of this study that included a novel method for the assessment of the potential for dose-response in early non-responding patients with schizophrenia.

METHODS/DESIGN

In this 6-week, international, multicenter, double-blind trial, eligible adults with acute schizophrenia were randomized to receive fixed doses of lurasidone 20 mg/day, 80 mg/day (active control), or placebo in a 1:2:1 ratio. Patients initially randomized to lurasidone 80 mg/day who did not have a Positive and Negative Syndrome Scale total score improvement ≥ 20% at Week 2 were re-randomized on a 1:1 basis to receive either lurasidone 80 mg/day or lurasidone 160 mg/day for the remainder of the trial. All other groups remained on their initially assigned treatment. The formal primary objective of the study was to evaluate the efficacy of low-dose lurasidone (20 mg/day) compared to placebo; secondary objectives included evaluating the efficacy of lurasidone 80 mg/day versus 160 mg/day in early non-responders, and evaluating the efficacy of lurasidone in all subjects initially randomized to 80 mg/day versus placebo.

DISCUSSION

Since a lack of early improvement predicts poor response to short-term antipsychotic treatment in patients with schizophrenia, several treatment strategies have been proposed to enhance treatment outcome in early non-responders. A novel clinical trial design involving a placebo arm and re-randomization of early non-responders to increased or maintained antipsychotic dose was developed. The study design described in this report provides a robust method to assess the value of antipsychotic dose escalation in patients with schizophrenia who demonstrate poor initial treatment response.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01821378; initial registration March 22, 2013.

Antipsychotics inhibit glucose transport: Determination of olanzapine binding site in Staphylococcus epidermidis glucose/H(+) symporter

The antipsychotic drug olanzapine is widely prescribed to treat schizophrenia and other psychotic disorders. However, it often causes unwanted side effects, including diabetes, due to disruption of insulin-dependant glucose metabolism through a mechanism yet to be elucidated. To determine if olanzapine can affect the first step in glucose metabolism - glucose transport inside cells - we investigated the effect of this drug on the transport activity of a model glucose transporter. The glucose transporter from Staphylococcus epidermidis (GlcPSe) is specific for glucose, inhibited by various human glucose transporter (GLUT) inhibitors, has high sequence and structure homology to GLUTs, and is readily amenable to transport assay, mutagenesis, and computational modeling. We found that olanzapine inhibits glucose transport of GlcPSe with an IC50 0.9 ± 0.1 mM. Computational docking of olanzapine to the GlcPSe structure revealed potential binding sites that were further examined through mutagenesis and transport assay to identify residues important for olanzapine inhibition. These investigations suggest that olanzapine binds in a polar region of the cytosolic part of the transporter, and interacts with residues R129, strictly conserved in all GLUTs, and N136, conserved in only a few GLUTs, including the insulin-responsive GLUT4. We propose that olanzapine inhibits GlcPSe by impeding the alternating opening and closing of the substrate cavity necessary for glucose transport. It accomplishes this by disrupting a key salt bridge formed by conserved residues R129 and E362, that stabilizes the outward-facing conformation of the transporter.

Reducing the rates of prescribing high-dose antipsychotics and polypharmacy on psychiatric inpatient and intensive care units: results of a 6-year quality improvement programme

BACKGROUND

There is no conclusive evidence that either high doses or combinations of antipsychotics are more effective than standard doses or monotherapy alone. Nonetheless, prescription of both remains prevalent in the UK. In 2006 the South London and Maudsley NHS Foundation Trust (SLAM) participated in a national survey of prescription of antipsychotic medications, organized by the Prescribing Observatory for Mental Health. Over half of the patients on SLAM inpatient or psychiatric intensive care units were prescribed a high-dose antipsychotic or a combination of antipsychotics. Prescribing high-dose antipsychotics and polypharmacy in SLAM was found to be among the highest in the UK.

AIM

To assess the impact of a 6-year quality improvement programme aimed at reducing the rates of prescribing high-dose antipsychotics and polypharmacy on SLAM inpatients and psychiatric intensive care units.

RESULTS

There was a significant reduction between baseline and final survey in the rates of prescription of both high-dose antipsychotics and polypharmacy on SLAM inpatients and intensive care units (58% versus 10% p < 0.0001 and 57% versus 16%, p < 0.0001 respectively). The proportion of patients at final survey prescribed a high-dose antipsychotic and a combination was substantially lower in SLAM than in the national sample (10% versus 28%, p < 0.0001 and 16% versus 38%, p < 0.0001 respectively).

CLINICAL IMPLICATIONS

A sustained change in the prescribing culture of an organization can be achieved through a targeted improvement programme.

Placebo response in antipsychotic clinical trials: a meta-analysis

IMPORTANCE

Because increasing placebo response rates decrease drug-placebo differences and increase the number of failed trials, it is imperative to determine what is causing this trend.

OBJECTIVES

To investigate the relationship between antipsychotic medication and placebo response by publication year, and to identify associated study design and implementation variables.

DATA SOURCES

MEDLINE, PsycINFO, and PubMed were searched to identify randomized clinical trials of antipsychotic medications published from 1960 to July 2013.

STUDY SELECTION

Included were randomized clinical trials lasting 4 to 24 weeks, contrasting antipsychotic medication with placebo or an active comparator, and enrolling patients 18 years of age or older with schizophrenia or schizoaffective disorder.

DATA EXTRACTION AND SYNTHESIS

Standardized mean change scores were calculated for each treatment arm, plotted against publication year, and tested with Spearman rank correlation coefficients. Hierarchical linear modeling identified factors associated with the standardized mean change across medication and placebo treatment arms.

MAIN OUTCOMES AND MEASURES

We hypothesized that the mean change in placebo-treated patients would significantly increase from 1960 to the present, that a greater change would be observed in active comparator vs placebo-controlled trials, and that more protocol visits would increase the symptom change observed.

RESULTS

In the 105 trials examined, the mean change observed in placebo arms increased significantly with year of publication (n=39, r=0.52, P=.001), while the mean change in effective dose medication arms decreased significantly (n=208, r=-0.26, P<.001). Significant interactions were found between assignment to effective dose medication and publication year (t260=-5.55, P<.001), baseline severity (t260=5.08, P<.001), and study duration (t260=-3.76, P<.001), indicating that the average drug-placebo difference significantly decreased over time, with decreasing baseline severity and with increasing study duration. Medication treatment in comparator studies was associated with significantly more improvement than medication treatment in placebo-controlled trials (t93=2.73, P=.008).

CONCLUSIONS AND RELEVANCE

The average treatment change associated with placebo treatment in antipsychotic trials increased since 1960, while the change associated with medication treatment decreased. Changes in randomized clinical trials leading to inflation of baseline scores, enrollment of less severely ill participants, and higher expectations of patients may all be responsible.

Effectiveness of antipsychotic drugs against hostility in patients with schizophrenia in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study

INTRODUCTION

Aggressive behavior can be a dangerous complication of schizophrenia. Hostility is related to aggression. This study aimed to compare the effects of olanzapine, perphenazine, risperidone, quetiapine, and ziprasidone on hostility in schizophrenia.

METHODS

We used the data that were acquired in the 18-month Phase 1 of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study. We analyzed the scores of the Positive and Negative Syndrome Scale (PANSS) hostility item in a subset of 614 patients who showed at least minimal hostility (a score ≥ 2) at baseline.

RESULTS

The primary analysis of hostility indicated an effect of difference between treatments (F(4,1487) = 7.78, P < 0.0001). Olanzapine was significantly superior to perphenazine and quetiapine at months 1, 3, 6, and 9. It was also significantly superior to ziprasidone at months 1, 3, and 6, and to risperidone at months 3 and 6.

DISCUSSION

Our results are consistent with those of a similar post-hoc analysis of hostility in first-episode subjects with schizophrenia enrolled in the European First-Episode Schizophrenia Trial (EUFEST) trial, where olanzapine demonstrated advantages compared with haloperidol, quetiapine, and amisulpride.

CONCLUSION

Olanzapine demonstrated advantages in terms of a specific antihostility effect over the other antipsychotics tested in Phase 1 of the CATIE trial.

Almost all antipsychotics result in weight gain: a meta-analysis

Introduction

Antipsychotics (AP) induce weight gain. However, reviews and meta-analyses generally are restricted to second generation antipsychotics (SGA) and do not stratify for duration of AP use. It is hypothesised that patients gain more weight if duration of AP use is longer.

Method

A meta-analysis was conducted of clinical trials of AP that reported weight change. Outcome measures were body weight change, change in BMI and clinically relevant weight change (7% weight gain or loss). Duration of AP-use was stratified as follows: ≤6 weeks, 6–16 weeks, 16–38 weeks and >38 weeks. Forest plots stratified by AP as well as by duration of use were generated and results were summarised in figures.

Results

307 articles met inclusion criteria. The majority were AP switch studies. Almost all AP showed a degree of weight gain after prolonged use, except for amisulpride, aripiprazole and ziprasidone, for which prolonged exposure resulted in negligible weight change. The level of weight gain per AP varied from discrete to severe. Contrary to expectations, switch of AP did not result in weight loss for amisulpride, aripiprazole or ziprasidone. In AP-naive patients, weight gain was much more pronounced for all AP.

Conclusion

Given prolonged exposure, virtually all AP are associated with weight gain. The rational of switching AP to achieve weight reduction may be overrated. In AP-naive patients, weight gain is more pronounced.

Pharmacotherapy of treatment-resistant schizophrenia: a clinical perspective

A significant number of patients with schizophrenia do not respond adequately to an initial antipsychotic trial. As first step within a treatment algorithm for therapy-refractory schizophrenia 'pseudoresistance' should be ruled out (eg, re-evaluation of the diagnosis, comorbidities, compliance and adherence in terms of medication intake, adequate dose and treatment duration, and achievement of sufficient plasma levels). In case of treatment resistance, two strategies that are often used in clinical routine care contain dose increase of the current administered antipsychotic drug (dose escalation, high-dose treatment) and switch to another, new antipsychotic. Although the response rates for both options are generally rather low, we see from the evidence-based perspective a slight advantage of the switching strategy (preferably to an antipsychotic with a different receptor-binding profile) compared to a high-dose treatment. After treatment failures with at least two different antipsychotic drugs, a monotherapy with clozapine is considered to be the treatment option of first choice. At present, pharmacological combination and augmentation strategies cannot be regarded as a generally recommendable evidence-based treatment method. Antipsychotic monotherapy should be preferably sought. In case of combination treatment, it appears more appropriate to combine preferentially two antipsychotics with different receptor-binding profiles. Augmentation of antipsychotics with other agents should be used primarily to treat specific target symptoms.

Common use of high doses of antipsychotic medications in older Asian patients with schizophrenia (2001-2009)

OBJECTIVE

This study aimed to examine the use of high doses of antipsychotic medications (≥600 mg/day chlorpromazine equivalent) in older Asian patients with schizophrenia and its demographic and clinical correlates.

METHOD

Information on hospitalized patients with schizophrenia aged ≥50 years was extracted from the database of the Research on Asian Psychotropic Prescription Patterns study (2001-2009). Data on 2203 patients in six Asian countries and territories, including China, Hong Kong, Japan, Korea, Singapore and Taiwan, were analyzed. Socio-demographic and clinical characteristics and antipsychotic prescriptions were recorded.

RESULTS

The frequency for high-dose antipsychotic medications was 36.0% overall, with 38.4% in 2001, 33.3% in 2004 and 36.0% in 2009. Multiple logistic regression analysis of the whole sample showed that compared to patients receiving low-medium antipsychotic doses, those on high doses had a longer illness duration (odds ratio (OR): 2.0, 95% confidence interval (CI):1.2-3.3, p = 0.008), were more likely in the 50-59-year group (OR: 0.95, 95% CI: 0.94-0.97, p < 0.001), more often had current positive (OR: 1.5, 95% CI: 1.2-1.8, p < 0.001) or negative symptoms (OR: 1.3, 95% CI: 1.03-1.6, p = 0.03), and more commonly received antipsychotic polypharmacy (OR: 5.3, 95% CI: 4.1-6.7, p < 0.001). Extrapyramidal symptoms (p = 0.25) and tardive dyskinesia (p = 0.92) were not more frequent in the high-dose group.

CONCLUSIONS

High doses of antipsychotic medications were used in more than one third of older Asian patients with schizophrenia. The reasons for the frequent use of high antipsychotic doses in older Asian patients warrant further investigation.

The possibility that requiring high-dose olanzapine cannot be explained by pharmacokinetics in the treatment of acute-phase schizophrenia

We examined clinical characteristics including serum olanzapine concentrations for acute schizophrenia patients who required above conventional doses. We performed a rater-blinded, randomized clinical trial in 12 psychiatric emergency sites. Eligible patients were 18-64 years old and met diagnostic criteria for schizophrenia, acute schizophrenia-like psychotic disorder, or schizoaffective disorder. A total of 42 patients were randomly assigned by means of sealed envelopes to receive risperidone (3-12 mg/day; n=20) and olanzapine (10-40 mg/day; n=22), with follow-up at 8 weeks. The Negative score of the Positive and Negative Syndrome Scale was significantly higher in patients who required high doses than in patients who responded to conventional doses. Serum olanzapine concentrations at the time of oral 20mg/day could be obtained from 5 out of 7 patients who subsequently required high-dose olanzapine. All values were more than 30 ng/mL after 11-16 h from dosing to sample collection, and the mean value was 47.876 (S.D. 21.546) ng/mL. Such concentrations are appropriate with respect to a therapeutic range of 20-50 ng/mL. The present study has shown evidence that the reason for requiring high-dose olanzapine cannot be explained by pharmacokinetics in the treatment of acute-phase schizophrenia.

Antipsychotic response in first-episode schizophrenia: efficacy of high doses and switching

Clinicians treating schizophrenia routinely employ high doses and/or antipsychotic switching to achieve response. However, little is actually known regarding the value of these interventions in early schizophrenia. Data were gathered from a treatment algorithm implemented in patients with first-episode schizophrenia that employs two antipsychotic trials at increasing doses before clozapine. Patients were initially treated with either olanzapine or risperidone across three dose ranges, (low, full, high), and in the case of suboptimal response were switched to the alternate antipsychotic. We were interested in the value of (a) high dose treatment and (b) antipsychotic switching. A total of 244 patients were evaluated, with 74.5% (184/244) responsive to Trial 1, and only 16.7% (10/60) responsive to Trial 2. Percentage of response for subjects switched from olanzapine to risperidone was 4.0% (1/25) vs. 25.7% (9/35) for those switched from risperidone to olanzapine. High doses yielded a 15.5% response (14.6% for risperidone vs. 16.7% for olanzapine).The present findings concur with other research indicating that response rate to the initial antipsychotic trial in first-episode schizophrenia is robust; thereafter it declines notably. In general, the proportion of responders to antipsychotic switching and high dose interventions was low. For both strategies olanzapine proved superior to risperidone, particularly in the case of antipsychotic switching (i.e. risperidone to olanzapine vs. vice versa). It remains to be established whether further antipsychotic trials are associated with even greater decrements in rate of response. Findings underscore the importance of moving to clozapine when treatment resistance has been established.

Pharmacogenetics of olanzapine metabolism

The pharmacokinetics of the atypical antipsychotic, olanzapine, display large interindividual variation leading to multiple-fold differences in drug exposure between patients at a given dose. This variation in turn gives rise to the need for individualized dosing in order to avoid concentration-dependent adverse effects or therapeutic failure. Genetically determined differences in olanzapine metabolism represent a less studied source of variability in comparison to environmental and physiological factors. In this review, we summarize available in vitro and in vivo data addressing the influence of polymorphisms in drug-metabolizing enzymes on olanzapine serum exposure. The polymorphic CYP2D6 enzyme appears to have no significant influence on olanzapine steady-state serum concentrations. The formation of the various olanzapine metabolites is influenced by polymorphisms in the genes coding for CYP1A2, CYP1A expression regulator AHR, UGT1A4 and UGT2B10, as well as FMO3. An impact on steady-state olanzapine serum concentrations has been suggested for variants of CYP1A2 and UGT1A4, with somewhat conflicting findings. The potential involvement of FMO1 and CYP3A43 in olanzapine disposition has also been suggested but needs future validation.

Olanzapine: a systematic review and meta-regression of the relationships between dose, plasma concentration, receptor occupancy, and response

OBJECTIVE

To conduct a systematic review examining the relationships between olanzapine dose, clinical outcome, dopamine occupancy, and plasma concentration; and to evaluate the potential for therapeutic drug monitoring.

METHODS

A search using Embase, Medline, and Pubmed was conducted; and the literature was systematically reviewed. Studies meeting inclusion criteria were examined. The relationships between olanzapine dose, response, dopamine occupancy, and concentration were analyzed using statistical regression.

RESULTS

Ten studies were included in the analysis for dose-response. The effect size-dose relationship showed a typical dose-response curve with minimal rise in slope for doses higher than 10 mg/d. For the dose-occupancy relationship, 6 studies were included. Doses more than approximately 12 mg/d were sufficient to block 65% of striatal D2 receptors. Doses higher than 20 mg led to minimally higher receptor occupancies. Fifteen studies were included in the meta-regression of olanzapine mean concentrations. A linear relationship between mean plasma concentration and mean dose was observed.

CONCLUSIONS

Our review suggests that the likelihood of a favorable response with olanzapine is maximized at doses of 10 to 15 mg/d (perhaps lower in nonsmoking females). Higher doses may be considered if 15 mg is ineffective and if plasma level is less than 20 ng/mL on that dose. There is a direct linear relationship between olanzapine dose and plasma concentration. Therapeutic drug monitoring may be useful in patients who are suspected of nonadherence, where there is potential for a drug interaction, and in patients taking 15 mg/d or more and who have not reached clinical response.

Efficacy and safety of lurasidone 80 mg/day and 160 mg/day in the treatment of schizophrenia: a randomized, double-blind, placebo- and active-controlled trial

OBJECTIVE

This study was designed to evaluate the short-term efficacy and safety of once-daily lurasidone (80 mg/day and 160 mg/day) in the treatment of an acute exacerbation of schizophrenia.

METHODS

Participants, who were recently admitted inpatients with schizophrenia with an acute exacerbation of psychotic symptoms, were randomly assigned to 6 weeks of fixed-dose, double-blind treatment with lurasidone 80 mg (n=125), lurasidone 160 mg (n=121), quetiapine XR 600 mg (QXR-600 mg; n=119; active control included to test for assay sensitivity), or placebo (n=121), all dosed once daily in the evening. Efficacy was evaluated using a mixed-model repeated-measures analysis of the change from Baseline to Week 6 in Positive and Negative Syndrome Scale (PANSS) total score (the primary efficacy measure) and Clinical Global Impressions severity (CGI-S) score (the key secondary efficacy measure).

RESULTS

Treatment with both doses of lurasidone or with QXR-600 mg was associated with significantly greater improvement at Week 6 on PANSS total score, PANSS positive and negative subscale scores, and CGI-S score compared with placebo. The endpoint responder rate (≥ 20% improvement in PANSS total score) was higher in subjects treated with lurasidone 80 mg (65%; p<0.001), lurasidone 160 mg (79%; p<0.001), and QXR-600 mg (79%; p<0.001) compared with placebo (41%). The proportion of patients experiencing ≥ 7% weight gain was 4% for each lurasidone group, 15% for the QXR-600 mg group, and 3% for the placebo group. Endpoint changes in levels of cholesterol, triglycerides, and low-density lipoprotein (LDL) cholesterol were comparable for both lurasidone groups and placebo, while the QXR-600 mg group showed a significant median increase compared with the placebo group in levels of cholesterol (p<0.001), LDL cholesterol (p<0.01), and triglycerides (p<0.05).

CONCLUSIONS

Lurasidone 80 mg and 160 mg doses administered once-daily in the evening, were safe and effective treatments for subjects with acute schizophrenia, with increased response rates observed at the higher dose. Dose-related adverse effects were limited, and both doses were generally well-tolerated.

Efficacy of olanzapine in comparison with clozapine for treatment-resistant schizophrenia: evidence from a systematic review and meta-analyses

INTRODUCTION

Clozapine is considered the gold standard for the treatment of patients with treatment-resistant schizophrenia (TRS); however, randomized controlled trials (RCT) of olanzapine showed efficacy similar to clozapine in patients with TRS.

METHODS

A systematic review was conducted comparing clozapine with olanzapine in patients with TRS. Meta-analyses were performed for single outcome measures. Response to treatment was measured by the percentage of responders, or mean change or endpoint values of psychotic symptoms scales. Effect sizes were shown as relative risks (RR), or standardized mean differences, with 95% confidence intervals.

FINDINGS

Seven RCT were included, comprising 648 patients. Five meta-analyses were performed. Olanzapine and clozapine had similar effects on dropout rates (RR = 0.93, CI95% = 0.77-1.12), PANSS total endpoints (SMD = 0.21, CI95% = -0.04-0.46), and PANSS total mean changes (SMD = 0.08, CI95% = -0.01-0.027). Clozapine was superior to olanzapine for PANSS positive (SMD = 0.51, CI95% = 0.17-0.86) and negative (SMD = 0.50, CI95% = 0.16-0.85) subscales. There was a trend toward high doses of olanzapine producing higher effect sizes for this drug.

CONCLUSIONS

The results of this study suggest that clozapine is significantly more efficacious than olanzapine in improving positive and negative symptoms in TRS patients.