Switching from clozapine to zotepine in patients with schizophrenia: a 12-week prospective, randomized, rater blind, and parallel study

Analysis of clinical studies on clozapine from 2012-2022

Clozapine has been considered the "gold standard" in the treatment of schizophrenia for many years. Clozapine has a superior effect, particularly in the treatment of negative symptoms and suicidal behaviour. However, due to its numerous adverse reactions, clozapine is mainly used for treatment-resistant schizophrenia. The aim of this paper is to analyze the results of clinical studies on clozapine from 2012-2022. PubMed was used as the database. Sixty-four studies were included and categorised by topic. The pharmacokinetic properties of clozapine tablets and a clozapine suspension solution did not differ markedly. Clozapine was superior to olanzapine and risperidone in reducing aggression and depression. A long-term study showed that metabolic parameters changed comparably with olanzapine and clozapine after 8 years. Risperidone and ziprasidone can be used as an alternative to clozapine. Scopolamine, atropine drops, and metoclopramide are effective in the treatment of clozapine-induced hypersalivation. Eight drugs, including liraglutide, exenatide, metformin, and orlistat, are potentially effective in the treatment of clozapine-induced weight gain. Ziprasidone, haloperidol, and aripiprazole showed a positive effect on symptoms when added to clozapine. No investigated drug was superior to clozapine for the treatment of schizophrenia. Ziprasidone and risperidone can also be used well for the treatment of schizophrenia. In the treatment of clozapine-induced hypersalivation and weight gain, some drugs proved to be effective.

Clinical Outcomes after Clozapine Discontinuation in Patients with Schizophrenia: A Systematic Review

INTRODUCTION

Clozapine is the gold standard of treatment for patients with treatment-resistant schizophrenia. However, approximately 60% of those patients do not respond to clozapine; moreover, clinical outcomes after clozapine discontinuation are unclear so far. Therefore, we conducted a systematic review to clarify the outcomes after clozapine discontinuation.

METHODS

A systematic literature search was conducted, using MEDLINE and Embase with the following keywords: (clozapine AND (cessation* OR cease* OR withdraw* OR discontinu* OR halt* OR stop* OR switch*) AND (schizophreni* OR schizoaffective)).

RESULTS

A total of 28 clinical studies from 27 articles were identified and included in this systematic review. Three randomized controlled trials reported worsening of psychiatric symptoms. In 10 single-arm studies, the results of worsening and improving psychiatric symptoms were inconsistent. In one large retrospective cohort study, clozapine rechallenge, olanzapine, and antipsychotic polypharmacy had lower rehospitalization rates compared to no medication after clozapine discontinuation. In the other 14 retrospective studies, the vast majority showed worsening of clinical status after clozapine discontinuation. Among five studies on clinical outcomes after clozapine rechallenge, four reported improvements in clinical status in more than half of patients who rechallenged clozapine. The remaining study reported that the clozapine discontinuation-rechallenge group had a worse remission assessment score than the clozapine discontinuation-no rechallenge group.

DISCUSSION

Clinical outcomes generally worsen after clozapine discontinuation. Clozapine rechallenge and olanzapine may be considered following clozapine discontinuation. The outcomes after clozapine discontinuation in clozapine non-responders remain inconclusive; therefore, well-designed studies are warranted.

Reducing the Risk of Withdrawal Symptoms and Relapse Following Clozapine Discontinuation-Is It Feasible to Develop Evidence-Based Guidelines?

Clozapine is the only antipsychotic that is effective in treatment-resistant schizophrenia. However, in certain clinical situations, such as the emergence of serious adverse effects, it is necessary to discontinue clozapine. Stopping clozapine treatment poses a particular challenge due to the risk of psychotic relapse, as well as the development of withdrawal symptoms. Despite these challenges for the clinician, there is currently no formal guidance on how to safely to discontinue clozapine. We assessed the feasibility of developing evidence-based recommendations for (1) minimizing the risk of withdrawal symptoms, (2) managing withdrawal phenomena, and (3) commencing alternatives treatment when clozapine is discontinued. We then evaluated the recommendations against the Appraisal of Guidelines for Research and Evaluation (AGREE) II criteria. We produced 19 recommendations. The majority of these recommendation were evidence-based, although the strength of some recommendations was limited by a reliance of studies of medium to low quality. We discuss next steps in the refinement and validation of an evidence-based guideline for stopping clozapine and identify key outstanding questions.

Clinical outcomes after clozapine discontinuation in responders versus nonresponders: a retrospective chart review

No studies have compared clinical outcomes after discontinuation of clozapine between patients who responded to clozapine and those who did not. Therefore, we examined 1-year clinical outcomes after clozapine discontinuation in responders and nonresponders. We reviewed data on patients who discontinued clozapine and retrospectively followed them for 1 year. Clinical information was collected from medical records starting at the initiation of clozapine administration, at discontinuation and at 1 year after discontinuation. In addition, clinical status was assessed using the Clinical Global Impression - Severity (CGI-S) and Clinical Global Impression - Improvement (CGI-I) scales. We classified the patients into clozapine responder and nonresponder groups according to the CGI-I score. Thirty-nine patients were enrolled in this study. Olanzapine was the most common antipsychotic prescribed after clozapine discontinuation in both the responder and nonresponder groups. The mean CGI-S score significantly increased 1 year after clozapine discontinuation in the responder group and significantly decreased in the nonresponder group; there was a significant difference in changes in the CGI-S scores between the groups. The difference remained significant after controlling for clozapine dose and duration of treatment. The findings suggest that clinicians may consider continuing and discontinuing clozapine treatment for patients who responded to clozapine and those who did not, respectively.

Clozapine discontinuation withdrawal symptoms in schizophrenia

Clozapine is an atypical antipsychotic used in treatment-resistant schizophrenia. Whilst clozapine is highly effective, there are some clinical scenarios, such as the emergence of severe side effects, that necessitate its discontinuation. There is an emerging literature suggesting that discontinuing antipsychotics, in particular clozapine, can cause an array of withdrawal symptoms. We review the evidence for the existence of clozapine-induced withdrawal symptoms, and in particular focus on withdrawal-associated psychosis, cholinergic rebound, catatonia and serotonergic discontinuation symptoms. To date, there has been surprisingly little clinical guidance on how to minimise the likeliness of withdrawal symptoms in patients who are stopped on clozapine abruptly or gradually. We discuss the key outstanding questions in this area and why there is a need for guidance on the management of withdrawal symptoms associated with clozapine discontinuation.

Reliability of the Glasgow Antipsychotic Side-effects Scale for Clozapine Japanese version (GASS-C-J)

The purpose of this study was to develop the Glasgow Antipsychotic Side effects Scale for Clozapine Japanese version (GASS-C-J) and examine its reliability to assess clozapine-related side effects. We developed the GASS-C-J using forward and backward translation. Semantic equivalence of the GASS-C-J to the GASS-C was confirmed by the original author. We then administered the GASS-C-J twice to 109 patients on clozapine treatment at two psychiatric hospitals in Japan. We assessed the internal consistency and test-retest reliability of the GASS-C-J using Cronbach's alpha and weighted kappa coefficient, respectively. We also examined if discrepancies in each GASS-C-J item score between the first and second rating were correlated with items of the Brief Evaluation of Psychosis Symptom Domains (BE-PSD). The Cronbach's alpha coefficient of the GASS-C-J at the first and second rating was 0.78 (95% CI: 0.72 to 0.84) and 0.82 (95% CI: 0.76 to 0.88), respectively. The weighted kappa coefficient of individual and total GASS-C-J item scores ranged from 0.45 to 0.88. Some symptom domains were correlated with discrepancies in specific items of the GASS-C-J: psychotic symptoms and nausea/vomiting (rs = 0.27), thirst (rs = 0.31), and appetite/weight gain (rs = 0.27); disorganized thinking and urinary incontinence (rs = 0.26); depression/anxiety and myoclonus (rs = 0.25), hypersalivation (rs = -0.27), and blurred vision (rs = -0.22). These findings demonstrate that the GASS-C-J can be used in clinical and research settings as a reliable scale to assess clozapine-related side effects.

Switching from clozapine to paliperidone palmitate-3-monthly improved obesity, hyperglycemia and dyslipidemia lowering antipsychotic dose equivalents in a treatment-resistant schizophrenia cohort

Clozapine, an antipsychotic developed in 1958, is considered the gold standard and the treatment of choice in treatment-resistant schizophrenia despite its side effects and despite 40-70% of these patients not responding to clozapine. In the last decade, new antipsychotics, such as paliperidone palmitate (PP), have emerged as well as its long acting-injectable (LAI) formulations, available as PP-1-monthly (PP1M) and the newest PP-3-montlhy (PP3M). Despite paliperidone having shown a similar efficacy as others antipsychotics for the treatment of schizophrenia, and that PP3M has been shown to reduce relapses compared to oral formulations, no study has been carried out in treatment-resistant schizophrenia. The aim of our study was to carry out an exploratory evaluation of endocrine and hepatic profiles as well as the concomitant treatments associated to PP3M vs. clozapine, the gold standard, in patients with treatment-resistant schizophrenia. We designed a retrospective study. A total number of 33 patients previously diagnosed as schizophrenics treatment-resistant, who were prescribed clozapine followed by PP1M and PP3M when available, were selected. Demographic data, BMI, hepatic enzymes (glutamic oxaloacetic transaminase, glutamate-pyruvate transaminase and gamma-glutamyl transferase (GGT)], thyroid function (thyroid stimulating hormone), blood platelets and both white and red blood cells as well as the use of concomitant antipsychotics, benzodiazepines and biperiden were compared under treatment with clozapine and PP3M. Antipsychotics and benzodiazepines dosages were compared using by the defined daily dose (DDD) method and haloperidol or diazepam dose equivalents. All statistical analyses were performed using the paired Student t-test for repeated measures. Our data showed that patients under treatment with PP3M showed a significant decrease in BMI (P < 0.01), glucose (P < 0.01), cholesterol (P < 0.05) and triglycerides (P < 0.01) when compared with basal values under treatment with clozapine. Hepatic cholestasis enzyme, GGT, were significantly elevated (P < 0.05) under treatment with clozapine when compared to PP3M. Switching clozapine to PP3M led to a significant lower pharmacological exposure to antipsychotics, by both the DDD (P < 0.05) and haloperidol dose equivalents (P < 0.001) methods without increasing the dose of benzodiazepines while biperiden was more used under PP3M. Finally, antipsychotic monotherapy was higher and less polypharmacy was used with PP3M. In conclusion, our findings suggest that switching clozapine to PP3M improved endocrine and hepatic profile with a lower total exposure to antipsychotics. More studies are needed to truly establish the role of PP3M in treatment-resistant schizophrenia and should be compared against clozapine by using clinical trials.

Antipsychotic-induced tardive dyskinesia: update on epidemiology and management

PURPOSE OF REVIEW

To provide an update on the frequency of antipsychotic-induced tardive dyskinesia and its management in patients with schizophrenia spectrum disorders in studies published since the last systematic review in 2008.

RECENT FINDINGS

Recent data about antipsychotic-induced tardive dyskinesia in patients with schizophrenia underscore the superiority of newer generation antipsychotics (21%) over first-generation antipsychotics (30%) with respect to prevalence and incidence rates. Regarding recently tested management strategies, the new vesicular monoamine transporter 2 inhibitors valbenazine and deutetrabenazine have been found to be effective and may be considered as first-line pharmacotherapy for tardive dyskinesia. Owing to quality issues of randomized controlled trials and/or small sample sizes, limited and conflicting evidence remains for most treatment strategies.

SUMMARY

The reviewed literature reveals lower prevalence rates of antipsychotic-induced tardive dyskinesia in patients treated with newer generation compared with first-generation antipsychotics. The evidence of vesicular monoamine transporter 2 inhibitors as a first-line therapy for tardive dyskinesia is well supported by several controlled clinical trials.

Comparative efficacy and tolerability of 15 antipsychotic drugs in schizophrenia: a multiple-treatments meta-analysis

BACKGROUND

The question of which antipsychotic drug should be preferred for the treatment of schizophrenia is controversial, and conventional pairwise meta-analyses cannot provide a hierarchy based on the randomised evidence. We aimed to integrate the available evidence to create hierarchies of the comparative efficacy, risk of all-cause discontinuation, and major side-effects of antipsychotic drugs.

METHODS

We did a Bayesian-framework, multiple-treatments meta-analysis (which uses both direct and indirect comparisons) of randomised controlled trials to compare 15 antipsychotic drugs and placebo in the acute treatment of schizophrenia. We searched the Cochrane Schizophrenia Group's specialised register, Medline, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for reports published up to Sept 1, 2012. Search results were supplemented by reports from the US Food and Drug Administration website and by data requested from pharmaceutical companies. Blinded, randomised controlled trials of patients with schizophrenia or related disorders were eligible. We excluded trials done in patients with predominant negative symptoms, concomitant medical illness, or treatment resistance, and those done in stable patients. Data for seven outcomes were independently extracted by two reviewers. The primary outcome was efficacy, as measured by mean overall change in symptoms. We also examined all-cause discontinuation, weight gain, extrapyramidal side-effects, prolactin increase, QTc prolongation, and sedation.

FINDINGS

We identified 212 suitable trials, with data for 43 049 participants. All drugs were significantly more effective than placebo. The standardised mean differences with 95% credible intervals were: clozapine 0·88, 0·73-1·03; amisulpride 0·66, 0·53-0·78; olanzapine 0·59, 0·53-0·65; risperidone 0·56, 0·50-0·63; paliperidone 0·50, 0·39-0·60; zotepine 0·49, 0·31-0·66; haloperidol 0·45, 0·39-0·51; quetiapine 0·44, 0·35-0·52; aripiprazole 0·43, 0·34-0·52; sertindole 0·39, 0·26-0·52; ziprasidone 0·39, 0·30-0·49; chlorpromazine 0·38, 0·23-0·54; asenapine 0·38, 0·25-0·51; lurasidone 0·33, 0·21-0·45; and iloperidone 0·33, 0·22-0·43. Odds ratios compared with placebo for all-cause discontinuation ranged from 0·43 for the best drug (amisulpride) to 0·80 for the worst drug (haloperidol); for extrapyramidal side-effects 0·30 (clozapine) to 4·76 (haloperidol); and for sedation 1·42 (amisulpride) to 8·82 (clozapine). Standardised mean differences compared with placebo for weight gain varied from -0·09 for the best drug (haloperidol) to -0·74 for the worst drug (olanzapine), for prolactin increase 0·22 (aripiprazole) to -1·30 (paliperidone), and for QTc prolongation 0·10 (lurasidone) to -0·90 (sertindole). Efficacy outcomes did not change substantially after removal of placebo or haloperidol groups, or when dose, percentage of withdrawals, extent of blinding, pharmaceutical industry sponsorship, study duration, chronicity, and year of publication were accounted for in meta-regressions and sensitivity analyses.

INTERPRETATION

Antipsychotics differed substantially in side-effects, and small but robust differences were seen in efficacy. Our findings challenge the straightforward classification of antipsychotics into first-generation and second-generation groupings. Rather, hierarchies in the different domains should help clinicians to adapt the choice of antipsychotic drug to the needs of individual patients. These findings should be considered by mental health policy makers and in the revision of clinical practice guidelines.

FUNDING

None.