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.
: 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.
