BACKGROUND:: Treatment options for clozapine resistance are diverse whereas, in contrast, the evidence for augmentation or combination strategies is sparse.
AIMS:: We aimed to extract levels of evidence from available data and extrapolate recommendations for clinical practice.
METHODS:: We conducted a systematic literature search in the PubMed/MEDLINE database and in the Cochrane database. Included meta-analyses were assessed using Scottish Intercollegiate Guidelines Network criteria, with symptom improvement as the endpoint, in order to develop a recommendation grade for each clinical strategy identified.
RESULTS:: Our search identified 21 meta-analyses of clozapine combination or augmentation strategies. No strategies met Grade A criteria. Strategies meeting Grade B included combinations with first- or second-generation antipsychotics, augmentation with electroconvulsive therapy for persistent positive symptoms, and combination with certain antidepressants (fluoxetine, duloxetine, citalopram) for persistent negative symptoms. Augmentation strategies with mood-stabilisers, anticonvulsants, glutamatergics, repetitive transcranial magnetic stimulation, transcranial direct current stimulation or cognitive behavioural therapy met Grades C-D criteria only.
CONCLUSION:: More high-quality clinical trials are needed to evaluate the efficacy of add-on treatments for symptom improvement in patients with clozapine resistance. Applying definitions of clozapine resistance would improve the reporting of future clinical trials. Augmentation with second-generation antipsychotics and first-generation antipsychotics can be beneficial, but the supporting evidence is from low-quality studies. Electroconvulsive therapy may be effective for clozapine-resistant positive symptoms.
Clozapine constitutes the treatment of choice in patients with schizophrenia with persisting symptoms despite antipsychotics at adequate dose and treatment duration. However, an important proportion does not respond to optimal doses of clozapine, so the addition of a second antipsychotic might increase clinical response. Searching in Epistemonikos database, which is maintained by screening multiple databases, we identified 17 systematic reviews comprising 62 studies addressing the question of this article, including 26 randomized trials. We combined the evidence using meta-analysis and generated a summary of findings following the GRADE approach. We concluded adding a second antipsychotic to clozapine in patients with refractory schizophrenia probably leads to little or no difference in clinical response, and increases adverse effects.
INTRODUCTION: Meta-analyses are a convenient way for clinicians and researchers to review data regarding different interventions. Meta-analyses can overcome many of the limitations of individual studies, namely the power to detect differences, and help resolve the results of inconsistent studies.
AREAS COVERED: This paper is a review of meta-analyses of oral atypical antipsychotics for the treatment of schizophrenia, located through PubMed and the Cochrane Database of Systematic Reviews. A total of 91 meta-analyses were identified that included efficacy outcome data for the 10 atypical antipsychotics available in the USA (11 focused on clozapine, 17 for risperidone, 8 for olanzapine, 5 for quetiapine, 3 for ziprasidone, 10 for aripiprazole, 5 for paliperidone, 1 for iloperidone, 0 for asenapine or lurasidone, and 31 others that were classified more broadly). These include Cochrane Reviews and other similarly executed reports, as well as pooled analyses meta-tagged in PubMed as a meta-analysis.
EXPERT OPINION: In general, there is heterogeneity among the atypical antipsychotics in terms of efficacy, with clozapine evidencing consistent superiority over typical antipsychotics, trailed behind by olanzapine and risperidone. Meta-analyses generally do not support efficacy differences between the other atypical antipsychotics compared with the older typical agents. Although this review is focused on efficacy, other considerations are also important, including the large tolerability differences among all the agents and the need to individualize medication choice based on past history of therapeutic response, past history of tolerability issues and the individual's personal values and preferences.
CONTEXT AND OBJECTIVE: According to some cohort studies, the prevalence of refractory schizophrenia (RS) is 20-40 percent. Our aim was to evaluate the effectiveness and safety of aripiprazole, paliperidone, quetiapine and risperidone for treating RS. METHODS: This was a critical appraisal of Cochrane reviews published in the Cochrane Library, supplemented with reference to more recent randomized controlled trials (RCTs) on RS. The following databases were searched: Medical Literature Analysis and Retrieval System Online (Medline) (1966-2009), Controlled Trials of the Cochrane Collaboration (2009, Issue 2), Embase (Excerpta Medica) (1980-2009), Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs) (1982-2009). There was no language restriction. Randomized controlled trials, systematic reviews and meta-analyses evaluating atypical antipsychotics for treating RS were included. RESULTS: Seven Cochrane systematic reviews and 10 additional RCTs were included in this review. The data generally showed minor differences between the atypical antipsychotics evaluated and typical antipsychotics, regarding improvement in disease symptoms, despite better adherence to treatment with atypical antipsychotics. Risperidone was specifically evaluated in patients with RS in one of the systematic reviews included, with favorable outcomes, but without definitive superiority compared with other drugs of proven efficacy, like amisulpride, clozapine and olanzapine. CONCLUSIONS: The findings underscore the difficulty in treating these patients, with high dropout rates and treatment patterns of modest improvement in assessments of effectiveness. Atypical antipsychotics have advantages over typical antipsychotics mainly through their better safety profile, which leads to better adherence to treatment. A combination of antipsychotics may also be an option for some refractory patients.
: Treatment options for clozapine resistance are diverse whereas, in contrast, the evidence for augmentation or combination strategies is sparse.
AIMS:
: We aimed to extract levels of evidence from available data and extrapolate recommendations for clinical practice.
METHODS:
: We conducted a systematic literature search in the PubMed/MEDLINE database and in the Cochrane database. Included meta-analyses were assessed using Scottish Intercollegiate Guidelines Network criteria, with symptom improvement as the endpoint, in order to develop a recommendation grade for each clinical strategy identified.
RESULTS:
: Our search identified 21 meta-analyses of clozapine combination or augmentation strategies. No strategies met Grade A criteria. Strategies meeting Grade B included combinations with first- or second-generation antipsychotics, augmentation with electroconvulsive therapy for persistent positive symptoms, and combination with certain antidepressants (fluoxetine, duloxetine, citalopram) for persistent negative symptoms. Augmentation strategies with mood-stabilisers, anticonvulsants, glutamatergics, repetitive transcranial magnetic stimulation, transcranial direct current stimulation or cognitive behavioural therapy met Grades C-D criteria only.
CONCLUSION:
: More high-quality clinical trials are needed to evaluate the efficacy of add-on treatments for symptom improvement in patients with clozapine resistance. Applying definitions of clozapine resistance would improve the reporting of future clinical trials. Augmentation with second-generation antipsychotics and first-generation antipsychotics can be beneficial, but the supporting evidence is from low-quality studies. Electroconvulsive therapy may be effective for clozapine-resistant positive symptoms.
