BACKGROUND: Although clozapine is the most effective medication for treatment refractory schizophrenia, only 40% of people will meet response criteria. We therefore undertook a systematic review and meta-analysis of global literature on clozapine augmentation strategies. METHODS: We systematically reviewed PubMed, PsycINFO, Embase, Cochrane Database, Chinese Biomedical Literature Service System and China Knowledge Resource Integrated Database for randomised control trials of augmentation strategies for clozapine resistant schizophrenia. We undertook pairwise meta-analyses of within-class interventions and, where possible, frequentist mixed treatment comparisons to differentiate treatment effectiveness RESULTS: We identified 46 studies of 25 interventions. On pairwise meta-analyses, the most effective augmentation agents for total psychosis symptoms were aripiprazole (standardised mean difference: 0.48; 95% confidence interval: −0.89 to −0.07) fluoxetine (standardised mean difference: 0.73; 95% confidence interval: −0.97 to −0.50) and, sodium valproate (standardised mean difference: 2.36 95% confidence interval: −3.96 to −0.75). Memantine was effective for negative symptoms (standardised mean difference: −0.56 95% confidence interval: −0.93 to −0.20). However, many of these results included poor-quality studies. Single studies of certain antipsychotics (penfluridol), antidepressants (paroxetine, duloxetine), lithium and <i>Ginkgo biloba</i> showed potential, while electroconvulsive therapy was highly promising. Mixed treatment comparisons were only possible for antipsychotics, and these gave similar results to the pairwise meta-analyses. CONCLUSIONS: On the basis of the limited data available, the best evidence is for the use of aripiprazole, fluoxetine and sodium valproate as augmentation agents for total psychosis symptoms and memantine for negative symptoms. However, these conclusions are tempered by generally short follow-up periods and poor study quality. (PsycInfo Database Record (c) 2021 APA, all rights reserved)
INTRODUCTION: Although clozapine (CLZ) is considered the best evidence-based therapeutic option for treatment of resistant schizophrenia patients, a significant proportion of CLZ-treated patients show a partial or inadequate response to treatment, leading to increased healthcare cost and poor quality of life for affected individuals.
AREAS COVERED: This paper comprises a review of main research in CLZ augmentation strategies for treatment-refractory schizophrenia, with a focus on research conducted between 1990 and 2014. Databases that were searched include: PubMed, CINAHL, EMBASE PsychINFO, AgeLine and Cochrane Database of Systematic Reviews. Primary search terms were 'clozapine augmentation', 'clozapine and add-on' and 'treatment-resistant schizophrenia', with cross reference to specific agents covered in this article. We reviewed the available evidence on CLZ augmentation with antipsychotics, antidepressants, mood stabilizers and other agents.
EXPERT OPINION: Many drugs have been evaluated as CLZ add-on therapies without demonstrating convincing efficacy in treating refractory schizophrenia symptoms. More research is needed to better define outcomes in schizophrenia, the topic of treatment-resistance and more well-designed trials are required to establish true efficacy and safety of CLZ augmentation strategies.
A significant proportion of patients with schizophrenia receiving clozapine remain with partial response. In this group of patients findings regarding addition of various psychotropics to ongoing clozapine treatment for augmentation are controversial. In this review, literature regarding the efficacy and safety of adjunctive agents in clozapine resistant schizophrenic patients is examined. Augmentation agents added to clozapine in treatment resistant schizophrenic patients consist of antipsychotics, antidepressants, mood stabilizers, other agents (eg. omega 3 fatty acids and glutamatergic agents) and electroconvulsive therapy (ECT) in this review. The number of controlled studies evaluating augmentation of clozapine in schizophrenia patients are highest for risperidone and lamotrigine add on treatments. However, the results of recent meta-analyses studies do not support any benefit of either agent as adjunct to clozapine treatment. Some evidence regarding the success of clozapine augmentation with amisulpride, aripiprazole, mirtazapine, omega 3 fatty acids and ECT have been obtained which needs further clinical investigation. Current findings from relevant clinical studies point that theses studies have limitations of small sample size, variable definitions of clozapine resistance, heterogenity of outcome measures and methodological designs and that sufficient evidence does not yet exist regarding the success of various adjunctive treatments for clozapine resistant patients.
BACKGROUND: When schizophrenia patients have insufficient response to clozapine, pharmacological augmentation is often applied. This meta-analysis summarizes available evidence on efficacy of pharmacological augmentation of clozapine treatment in schizophrenia spectrum disorder. METHODS: Only double-blind randomized controlled studies were included. Primary outcome measure was total symptom severity, and secondary outcome measures were subscores for positive and negative symptoms. Effect sizes were calculated from individual studies and combined to standardized mean differences (Hedges’s <i>g</i>). RESULTS: Twenty-nine studies reporting on 15 different augmentations were included. Significant better efficacy than placebo on total symptom severity was observed for lamotrigine, citalopram, sulpiride, and CX516 (a glutamatergic agonist). The positive effect of lamotrigine disappeared after outlier removal. The other positive findings were based on single studies. Significantly better efficacy on positive symptom severity was observed for topiramate and sulpiride. The effect of topiramate disappeared after outlier removal. Results for sulpiride were based on a single randomized controlled trial. Citalopram, sulpiride, and CX516 showed better efficacy for negative symptoms than placebo, all based on single studies. CONCLUSIONS: Evidence for efficacy of clozapine augmentation is currently scarce. Efficacy of lamotrigine and topiramate were both dependent on single studies with deviating findings. The effect of citalopram, sulpiride, and CX516 were based on single studies. Thus, despite their popularity, pharmacological augmentations of clozapine are not (yet) demonstrated to be superior to placebo. (PsycInfo Database Record (c) 2021 APA, all rights reserved)
BACKGROUND: Treating the 20-30% of people with schizophrenia whose symptoms are resistant to treatment can be problematic. Adding lamotrigine to ongoing antipsychotic treatment has shown to be of benefit in preliminary studies.
OBJECTIVES: To evaluate the effects of adjuvant lamotrigine for people with schizophrenia and schizophrenia-like psychoses.
SEARCH METHODS: We searched the Cochrane Schizophrenia Group's Register (February 2006) and inspected references of all identified studies for further trials. We contacted relevant authors of trials for additional information.
SELECTION CRITERIA: We included all clinical randomised trials comparing lamotrigine with placebo or other antipsychotic augmentation strategies.
DATA COLLECTION AND ANALYSIS: We extracted data independently. For homogenous dichotomous data we calculated random effects relative risk (RR), 95% confidence intervals (CI) and, where appropriate, numbers needed to treat (NNT) on an intention-to-treat basis. For continuous data, we calculated weighted mean differences (WMD).
MAIN RESULTS: We found five relevant trials (total n=537), but no usable data on service outcomes, general functioning, behaviour, engagement with services, satisfaction with treatment or economic outcomes. Overall, reporting of data was poor. Those data we were able to use suggested that equal proportions of people allocated lamotrigine or placebo had no global response (n=208, 1 RCT, RR 1.06 CI 0.73 to 1.54). There was no significant difference between groups in the proportions of people whose mental state did not improve (n=297, 3 RCT, RR 1.26 CI 0.81 to 1.97). There was, however, a significant reduction in the PANSS total scores (n=67, 2 RCT, WMD -16.88 CI -8.57 to -25.18, p=0.0001), positive symptom sub-scale scores (n=65, 2 RCTs, WMD -5.10 CI -8.86 to -1.34) and negative symptom sub-scale scores (n=67, 2 RCTs, WMD -5.25, CI -7.07 to -3.43). Most cognitive measures showed no differences (n=329, 2 RCTs, RR not attaining BACS composite score of 0.5 1.10 CI 0.59 to 2.04). The proportion of participants leaving studies was about 25% at 12 weeks (n=537, 5 RCTs, RR 0.96 CI 0.71 to 1.29). The lamotrigine group did experience the outcome of any adverse effects significantly more frequent than people allocated placebo (n=429, 2 RCTs, RR 1.19 CI 1.02 to 1.38, NNH 10 CI 5 to 90). Among the many effects listed, only nausea was found to be significantly more (9%) in the lamotrigine group compared with placebo (n=465, 3 RCTs, RR 2.26 CI 1.05 to 4.88).
AUTHORS' CONCLUSIONS: Evidence for use of lamotrigine as an adjuvant for people with schizophrenia is not robust and large well-designed, conducted and reported real-world randomised trials are needed to determine its place in everyday clinical practice.
Approximately 40-70% of treatment-resistant schizophrenic patients fail to benefit from clozapine monotherapy or are partial responders. During the last years several clozapine adjunctive agents have come into clinical practice. This study aims to critically review all published randomized, double-blind, placebo-controlled clinical trials (RCTs) regarding the efficacy and safety of adjunctive agents in clozapineresistant schizophrenic or schizoaffective patients. A MEDLINE search for RCTs on clozapine adjunctive agents published from January 1980 to February 2004 was conducted. All identified papers were critically reviewed and examined against several methodological features as well as clinical and pharmacological parameters. Eleven trials including 270 patients, partial or non-responders to clozapine, assessed the efficacy of sulpiride, lithium, lamotrigine, fluoxetine, glycine, D-serine, D-cycloserine and ethyl-eicosapentanoate (E-EPA) as clozapine adjuncts. There were eight parallel-group and three crossover trials. The inclusion criteria varied widely. The duration as well as the dosage of clozapine monotherapy were reported adequate in only one trial. Plasma clozapine levels were assessed in only three trials. Main side-effects reported were hypersalivation, sedation, diarrhea, nausea, hyperprolactinaemia. The outcome favored clozapine augmentation with sulpiride, lamotrigine and E-EPA. Lithium was shown to benefit only schizoaffective patients. However, the methodological shortcomings of trials analyzed limit the impact of evidence provided. (PsycInfo Database Record (c) 2021 APA, all rights reserved)
Although clozapine is the most effective medication for treatment refractory schizophrenia, only 40% of people will meet response criteria. We therefore undertook a systematic review and meta-analysis of global literature on clozapine augmentation strategies.
METHODS:
We systematically reviewed PubMed, PsycINFO, Embase, Cochrane Database, Chinese Biomedical Literature Service System and China Knowledge Resource Integrated Database for randomised control trials of augmentation strategies for clozapine resistant schizophrenia. We undertook pairwise meta-analyses of within-class interventions and, where possible, frequentist mixed treatment comparisons to differentiate treatment effectiveness
RESULTS:
We identified 46 studies of 25 interventions. On pairwise meta-analyses, the most effective augmentation agents for total psychosis symptoms were aripiprazole (standardised mean difference: 0.48; 95% confidence interval: −0.89 to −0.07) fluoxetine (standardised mean difference: 0.73; 95% confidence interval: −0.97 to −0.50) and, sodium valproate (standardised mean difference: 2.36 95% confidence interval: −3.96 to −0.75). Memantine was effective for negative symptoms (standardised mean difference: −0.56 95% confidence interval: −0.93 to −0.20). However, many of these results included poor-quality studies. Single studies of certain antipsychotics (penfluridol), antidepressants (paroxetine, duloxetine), lithium and Ginkgo biloba showed potential, while electroconvulsive therapy was highly promising. Mixed treatment comparisons were only possible for antipsychotics, and these gave similar results to the pairwise meta-analyses.
CONCLUSIONS:
On the basis of the limited data available, the best evidence is for the use of aripiprazole, fluoxetine and sodium valproate as augmentation agents for total psychosis symptoms and memantine for negative symptoms. However, these conclusions are tempered by generally short follow-up periods and poor study quality. (PsycInfo Database Record (c) 2021 APA, all rights reserved)
