Perazine and carbamazepine in comparison to olanzapine in schizophrenia

Novel pharmacotherapy targeting the positive symptoms of schizophrenia

INTRODUCTION

The severity of positive symptoms in schizophrenia is associated with poor prognosis. About one-third of schizophrenia patients partially respond to treatment with available antipsychotics. The purpose of the present manuscript is to provide an updated overview of novel pharmacotherapy targeting positive symptoms in schizophrenia.

AREAS COVERED

A comprehensive research on the main database sources (PubMed, PsychINFO, Isi Web of Knowledge, MEDLINE, and EMBASE) was performed to obtain original articles published till 31st January 2023 about new pharmacological strategies for the treatment of positive symptoms in schizophrenia.

EXPERT OPINION

The most promising compounds include: lamotrigine, pro-cognitive-compounds (donepezil - in the short term, idazoxan and piracetam) and drugs acting partially or totally outside the Central Nervous System (CNS) (anti-inflammatory drugs: celecoxib, methotrexate; cardiovascular compounds: L-theanine, mononitrate isosorbide, propentofylline, sodium nitroprusside; metabolic regulators: diazoxide, allopurinol; others: bexarotene, raloxifene [in women]). The effectiveness of the latter compounds indicates that other biological systems, such as immunity or metabolism can be object of future research to identify pharmacological targets for positive symptoms of schizophrenia. Mirtazapine could be useful for treating negative symptoms without increasing the risk of a worsening of delusions/hallucinations. Nevertheless, the lack of replication of studies prevents to draw definitive conclusions and future studies are needed to confirm the findings presented in this overview.

Carbamazepine for schizophrenia

BACKGROUND

Many people with schizophrenia do not achieve a satisfactory treatment response with just antipsychotic drug treatment and various adjunct medications are used to promote additional response. The antiepileptic carbamazepine is one such drug.

OBJECTIVES

To examine whether carbamazepine or oxcarbazepine alone is an effective treatment for schizophrenia and schizoaffective psychoses and whether carbamazepine or oxcarbazepine augmentation of neuroleptic medication is an effective treatment for the same illnesses.

SEARCH METHODS

For the original version we searched The Cochrane Schizophrenia Group's Register of Trials (December 2001), The Cochrane Library (Issue 3, 2001), MEDLINE (1966-2001), EMBASE (1980-2001), Biological Abstracts (1980-2001), PsycLIT (1886-2001) and PSYNDEX (1974-2001). For the most recent update we searched the Cochrane Schizophrenia Group's Register of Trials in July 2012. We also inspected references of all identified studies for further trials and contacted relevant pharmaceutical companies and authors for additional data.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing carbamazepine or compounds of the carbamazepine family with placebo or no intervention, whether as sole treatment or as an adjunct to antipsychotic medication for the treatment of schizophrenia and/or schizoaffective psychoses.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For homogenous dichotomous data we calculated fixed-effect, risk ratio (RR), with 95% confidence intervals (CIs) on an intention-to-treat basis. For continuous data, we calculated mean differences (MD). We assessed the risk of bias for included studies and created a 'Summary of findings' table using GRADE.

MAIN RESULTS

The updated search did not reveal any further studies that met our inclusion criteria. The number of included studies therefore remains at 10 with the number of participants randomised still 283.One study comparing carbamazepine with placebo as the sole treatment for schizophrenia was abandoned early due to high relapse rate with 26 out of 31 participants relapsing by three months. No effect of carbamazepine was evident with no difference in relapse between the two groups (1 RCT n = 31, RR 1.07 CI 0.78 to 1.45). Another study compared carbamazepine with antipsychotics as the sole treatment for schizophrenia. No differences in terms of mental state were found when comparing 50% reduction in Brief Psychiatric Rating Scale (BPRS) scores (1 RCT n = 38, RR 1.23 CI 0.78 to 1.92). A favourable effect for carbamazepine was found when more people who received the antipsychotic (perphenazine) had parkinsonism (1 RCT n = 38, RR 0.03 CI 0.00 to 0.043). Eight studies compared adjunctive carbamazepine versus adjunctive placebo, we were able use GRADE for quality of evidence for these results. Adding carbamazepine to antipsychotic treatment was as acceptable as adding placebo with no difference between the numbers leaving the study early from each group (8 RCTs n = 182, RR 0.47 CI 0.16 to 1.35, very low quality evidence). Carbamazepine augmentation was superior compared with antipsychotics alone in terms of overall global improvement, but participant numbers were low (2 RCTs n = 38, RR 0.57 CI 0.37 to 0.88). There were no differences for the mental state outcome of 50% reduction in BPRS scores (6 RCTs n = 147, RR 0.86 CI 0.67 to 1.12, low quality evidence). Less people in the carbamazepine augmentation group had movement disorders than those taking haloperidol alone (1 RCT n = 20, RR 0.38 CI 0.14 to 1.02). No data were available for the effects of carbamazepine on subgroups of people with schizophrenia and aggressive behaviour, negative symptoms or EEG abnormalities or with schizoaffective disorder.

AUTHORS' CONCLUSIONS

Based on currently available randomised trial-derived evidence, carbamazepine cannot be recommended for routine clinical use for treatment or augmentation of antipsychotic treatment of schizophrenia. At present large, simple well-designed and reported trials are justified - especially if focusing on people with violent episodes and people with schizoaffective disorders or those with both schizophrenia and EEG abnormalities.

Perazine for schizophrenia

BACKGROUND

Perazine is an old phenothiazine derivative used for the treatment of people with schizophrenia and is reputed to have a low level of extrapyramidal adverse effects. As far as we are aware, its use is limited to Germany, Poland, the former Yugoslavia and the Netherlands.

OBJECTIVES

To examine the effects of perazine for those with schizophrenia or related psychoses in comparison with placebo, no treatment or other antipsychotic medications.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group Trials Register, which includes relevant randomised controlled trials from the bibliographic databases Biological Abstracts, CINAHL, The Cochrane Library, EMBASE, MEDLINE, PsycLIT, LILACS, PSYNDEX, Sociological Abstracts and Sociofile. We searched the references of all included studies for further trials. We contacted pharmaceutical companies and authors of trials. We updated this search on 16th July 2012.

SELECTION CRITERIA

We selected all randomised controlled trials that compared perazine with other treatments for people with schizophrenia or schizophrenia-like psychoses, or both.

DATA COLLECTION AND ANALYSIS

The review authors (SL, BH, BHe) independently inspected the citations and where possible abstracts and ordered papers for re-inspection and quality assessment. We independently extracted data. We calculated the risk ratio (RR) and 95% confidence interval (CI) using a random-effects model. For continuous data, we calculated mean differences (MD). We inspected all data for heterogeneity, assessed trials for risk of bias and created summary of findings tables using GRADE.

MAIN RESULTS

The review now includes seven trials with a total of 479 participants. In only one trial, with 95 participants, perazine appeared superior to 'active placebo' (trimipramine) at five weeks for the outcome of 'no important global improvement' (n = 95, RR 0.43 CI 0.2 to 0.8, low quality evidence), but there was no statistically significant difference in most measures of mental state. Perazine did not induce more general adverse events than placebo but more participants received at least one dose of antiparkinson medication (n = 95, RR 4.50 CI 1.0 to 19.5, very low quality evidence).Six small trials comparing perazine with other antipsychotics, including 384 participants in total, were incompletely reported and the outcomes were presented in various ways so that meta-analysis was not possible on most occasions. In the six studies, a similar number of participants receiving perazine or comparator antipsychotics (amisulpride, haloperidol, olanzapine, ziprasidone, zotepine) left the studies early (n = 384, RR 0.97 CI 0.68 to 1.38, low quality evidence). The results on efficacy could not be meta-analysed because the authors presented their results in very different ways. No obvious differences in adverse events between perazine and other antipsychotics could be derived from the limited data. Two haloperidol comparisons did not present extrapyramidal side-effects in a way that was suitable for use in meta-analysis, but three small comparisons with the second-generation antipsychotics zotepine and amisulpride showed no higher risk of akathisia (n = 111, RR 0.31 CI 0.1 to 1.1), dyskinesia (n = 111, RR 0.47 CI 0.1 to 3.5), parkinsonism (n = 81, RR 1.21 CI 0.5 2.8) or tremor (n = 40, RR 0.80 CI 0.3 to 2.6) with perazine.

AUTHORS' CONCLUSIONS

The number, size and reporting of randomised controlled perazine trials are insufficient to present firm conclusions about the properties of this antipsychotic. It is possible that perazine is associated with a similar risk of extrapyramidal side-effects as some atypical antipsychotics but this is based on small comparisons. This should be clarified in larger, well-designed trials.

Perazine for schizophrenia

BACKGROUND

Perazine is an old phenothiazine derivative used for the treatment of people with schizophrenia and is reputed to have a low level of extrapyramidal adverse effects. As far as we are aware, its use is limited to Germany, Poland, the former Yugoslavia and the Netherlands.

OBJECTIVES

To examine the effects of perazine for those with schizophrenia, and schizophrenia-like psychoses.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group's register which includes relevant randomised controlled trials from the bibliographic databases Biological Abstracts, CINAHL, The Cochrane Library, EMBASE, MEDLINE, PsycLIT, LILACS, PSYNDEX, Sociological Abstracts and Sociofile (last update of the review March 2005). We searched references of all included studies for further trials. We contacted pharmaceutical companies and authors of trials.

SELECTION CRITERIA

We selected all randomised controlled trials that compared perazine with other treatments for people with schizophrenia and/or schizophrenia-like psychoses.

DATA COLLECTION AND ANALYSIS

We independently (SL, BH) inspected citations and where possible abstracts and ordered papers for re-inspection and quality assessment. We independently extracted data. We excluded data if loss to follow up was greater than 50%. For homogeneous dichotomous data we calculated the Relative Risk (RR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) on an intention-to-treat basis. For continuous data, we calculated weighted mean differences (WMD). We inspected all data for heterogeneity.

MAIN RESULTS

We included six trials with a total of 288 participants. In only one trial with 95 participants, perazine appeared superior to 'active placebo' (trimipramine) at five weeks for the outcome of 'no important global improvement' (n=95, RR 0.43 CI 0.2 to 0.8, NNT 4 CI 2 to 13), but there was no statistically significant difference in most measures of mental state. Perazine did not induce more general adverse events than placebo, but more participants received at least one dose of antiparkinson medication (n=95, RR 4.50 CI 1.0 to 19.5, NNH 6 CI 4 to 33). Five small trials comparing perazine with other antipsychotics, including in total only 193 participants, were incompletely reported and the outcomes were presented in various ways so that meta-analysis was not possible in most occasions. A similar number of participants receiving perazine or comparator antipsychotics left the studies early (n=193, RR 0.85, CI 0.5 to 1.4). The results on efficacy were controversial and need further assessment by randomised controlled trials. No obvious differences in adverse events between perazine and other antipsychotics could be derived from the limited data. Two haloperidol comparisons did not present extrapyramidal side-effects in a suitable way for use in meta-analysis, but three small comparisons with the atypical antipsychotics zotepine and amisulpride showed no higher risk of akathisia (n=111, RR 0.31 CI 0.1 to 1.1), dyskinesia (n=111, RR 0.47 CI 0.1 to 3.5), parkinsonism (n=81, RR 1.21 CI 0.5 2.8) or tremor (n=40, RR 0.80 CI 0.3 to 2.6) with perazine.

AUTHORS' CONCLUSIONS

The number, size and reporting of randomised controlled perazine trials is insufficient to present firm conclusions about the properties of this antipsychotic. It is possible that perazine is associated with a similar risk of extrapyramidal side-effects as some atypical antipsychotics, and this should be clarified in larger, well-designed trials.