Ziprasidone vs clozapine in schizophrenia patients refractory to multiple antipsychotic treatments: the MOZART study

Heterogeneity and efficacy of antipsychotic treatment for schizophrenia with or without treatment resistance: a meta-analysis

Two important clinical questions are whether there is a subtype of schizophrenia which responds differently to clozapine relative to other antipsychotics, and whether greater efficacy of clozapine is dependent on the degree of treatment-resistance. The authors address this by examining both variability and magnitude of response in patients treated with clozapine and other antipsychotics for both treatment-resistant schizophrenia (TRS) and non-resistant schizophrenia. Double-blind randomised controlled trials comparing clozapine with other antipsychotics in patients with schizophrenia were identified using five databases. Standard deviations and means of change in total, positive, and negative symptoms were extracted. Variability ratio (VR) and coefficient of variation ratio (CVR) were used to quantify relative variability in symptom change. Hedges' g was used to quantify mean differences. Ten TRS studies (n = 822) and 29 non-TRS studies (n = 2566) were meta-analysed. Relative variability in change of total symptoms did not differ significantly between clozapine and other antipsychotics in TRS studies (VR = 1.84; 95%CI, 0.85-4.02). These findings were similar with CVR, and for positive and negative symptoms. Clozapine was superior to other antipsychotics in improving total symptoms in both TRS (g = 0.34; 95%CI, 0.13-0.56) and non-TRS (g = 0.20; 95%CI, 0.08-0.32) studies. Furthermore, clozapine was superior in improving positive symptoms in both study groups, but not for negative symptoms. Pooled effect sizes showed no significant difference between TRS and non-TRS studies. These findings do not support a subtype of schizophrenia which responds specifically to clozapine. Clozapine is more effective than other antipsychotics irrespective of treatment-resistance, arguing for its use more generally in schizophrenia. PROSPERO CRD42018086507.

Clozapine and tardive dyskinesia in patients with schizophrenia: A systematic review

BACKGROUND

It is commonly recommended that a switch to clozapine be implemented in the face of tardive dyskinesia, even if current treatment involves another "atypical" agent. However, reports do indicate clozapine carries a liability for tardive dyskinesia.

AIMS

This review sought to evaluate clozapine in relation to tardive dyskinesia in the context of available evidence.

METHODS

Medline, Embase, and PsycINFO databases were searched for studies published in English, using the keywords: clozapine AND tardive dyskinesia OR TD. References from major review articles were searched for additional relevant publications. Studies were included if they investigated: tardive dyskinesia in clozapine-treated patients diagnosed with schizophrenia spectrum disorders, and reported on two or more assessments of tardive dyskinesia severity measured by the Abnormal Involuntary Movement Scale; or clozapine's tardive dyskinesia liability.

RESULTS

In total, 513 unique citations were identified and 29 reports met the inclusion criteria. Thirteen studies suggest clozapine reduces dyskinetic symptoms over time (n=905 clozapine-treated participants); however, the minimum required dose and effect of withdrawal requires further investigation. The majority of reports which address clozapine's liability for tardive dyskinesia are case studies (11 of 14 reports, 79%), and clozapine was only the first-line treatment in one of the remaining three studies reporting treatment-emergent dyskinetic symptoms with clozapine in 12% of patients. No significant between-drug differences were identified comparing clozapine's risk to other atypical antipsychotics.

CONCLUSIONS

Research to date supports switching to clozapine for the purpose of reducing tardive dyskinesia risk and/or treating existing tardive dyskinesia, but prospective randomized controlled trials are necessary if we are to substantiate existing recommendations.

Increasing antipsychotic dose versus switching antipsychotic for non response in schizophrenia

BACKGROUND

Many people with schizophrenia do not respond to an initially prescribed antipsychotic drug. In such cases, one treatment strategy could be to increase the antipsychotic dose; and another strategy could be to switch to a different antipsychotic drug.

OBJECTIVES

To examine the efficacy of increasing the antipsychotic dose versus switching the antipsychotic drug in the treatment of non-responsive people with schizophrenia.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group Trials Register (10 June 2014, 6 October 2015, and 30 March 2017). We examined references of all included studies for further trials.

SELECTION CRITERIA

All relevant randomised controlled trials (RCTs) comparing increasing the antipsychotic dose versus switching to a different antipsychotic drug for people with schizophrenia who have not responded to their initial antipsychotic treatment.

DATA COLLECTION AND ANALYSIS

At least two review authors independently extracted data. We analysed dichotomous data using relative risks (RR) and their 95% confidence intervals (CIs). We analysed continuous data using mean differences (MD) and their 95% CIs. We assessed risk of bias for included studies and used GRADE to create a 'Summary of findings' table.

MAIN RESULTS

We include one RCT with relevant data on 29 participants in this review. The trial had a parallel design and was double-blind, but blinding procedures were not described. The trial included people who were non-responsive to fluphenazine 20 mg/day administered for 4 weeks. Participants were randomly assigned to continuing treatment with fluphenazine 20 mg/day, increasing the dose to fluphenazine 80 mg/day or switching to haloperidol 20 mg/day for four additional weeks. Data were reported only for 47 out of 58 initially randomised participants. The trial was published in 1993. The fact that only one RCT with a small sample size (N = 29) was included in the analysis limits the quality of the evidence. Overall, no clear difference was found between groups in terms of the three available outcomes: global state (number of participants with clinically relevant response (RR 1.63, 95% CI 0.17 to 15.99, very low quality evidence); general mental state (endpoint score, BPRS total) (MD 2.00, 95% CI -4.20 to 8.20, very low quality evidence); and negative symptoms (endpoint score, SANS) (MD 3.40, 95% CI -12.56 to 19.36). No data were reported for leaving the study early, adverse effects, time in hospital, quality of life, satisfaction with care and functioning.

AUTHORS' CONCLUSIONS

There is extremely limited evidence and no clear conclusions can be drawn. There is an urgent need for further trials in order to determine the optimal treatment strategy for people with schizophrenia who do not respond to their initial antipsychotic treatment.

Impact of Drug Induced Long QT Syndrome: A Systematic Review

Background

Drug induced long QT syndrome is quite common in daily clinical practice but its impact is unknown.

Methods

PubMed and EMBASE databases (until May 2, 2017) were searched to identify studies reporting drug induced long QT syndrome and followed the PRISMA guidelines. The main outcomes measured in these studies were QTc prolongation, ventricular arrhythmias, torsade de pointes (TdP) and death.

Results

Out of 176 non-duplicate reports, 36 studies satisfied inclusion criteria and provided data on patients exposed to drugs that can potentially cause long QT. Totally, 14,756 patients were exposed and 930 patients (6.3%) were found to have QTc prolongation. The number of males was 6,400 and females were 5,723 patients. The mean age of the patients was 43.8 ± 9.36 years. Ventricular arrhythmias were found in 379 patients (2.6%), 26 patients were found to have premature atrial contractions (PACs) and premature ventricular contractions (PVCs). TdP was found in 49 patients (0.33 %), sudden cardiac death (SCD) was found in five patients and 586 patients were found to have all-cause mortality.

Conclusions

Around 6% of patients have risk of QT prolongation when exposed but only 0.3% developed TdP and 2.6% developed ventricular arrhythmias. Risk of developing arrhythmias is higher with concomitant use of multiple QT prolonging drugs.

Clozapine Response Rates among People with Treatment-Resistant Schizophrenia: Data from a Systematic Review and Meta-Analysis

Clozapine is the most effective antipsychotic for the 25% to 33% of people with schizophrenia who are treatment resistant, but not all people achieve response. Using data from a previously published clozapine systematic review and meta-analysis, we explored the proportion of people who achieved response and examined the absolute and percentage change in Positive and Negative Syndrome Scale (PANSS) scores. Overall, 40.1% (95% confidence interval [CI], 36.8%-43.4%) responded, with a mean reduction in PANSS of 22.0 points (95% CI, 20.9-23.1), a reduction of 25.8% (95% CI, 24.7%-26.9%) from baseline. These reductions are clinically meaningful. A 40% response rate to clozapine suggests that 12% to 20% of people with schizophrenia will be ultra-resistant.

Clozapine v. first- and second-generation antipsychotics in treatment-refractory schizophrenia: systematic review and meta-analysis

BACKGROUND

Although clozapine is the 'gold standard' for treatment-refractory schizophrenia, meta-analyses of clozapine for this condition are lacking.

AIMS

We conducted a systematic review and meta-analysis of clozapine treatment for people with treatment-refractory schizophrenia.

METHOD

We searched the Cochrane Schizophrenia Group's trial register, PubMed and EMBASE and hand-searched key papers for randomised controlled trials of clozapine for treatment-refractory schizophrenia.

RESULTS

Twenty-one papers with 25 comparisons were included. The number needed to treat was 9. Clozapine was superior for positive symptoms in both the short and long term. In the short term only clozapine was superior for total and negative symptoms, with higher response rates. Both funding source and dosage affected results. Higher baseline psychosis scores predicted better outcomes for clozapine in a meta-regression.

CONCLUSIONS

Clozapine is superior for treatment-refractory disorder but if there is no response by 6 months medications with lower adverse reactions should be considered.

Atypical antipsychotics in the treatment of early-onset schizophrenia

Atypical antipsychotics (AAPs) have been successfully used in early-onset schizophrenia (EOS). This review summarizes the randomized, double-blind, controlled studies of AAPs in EOS, including clozapine, risperidone, olanzapine, aripiprazole, paliperidone, quetiapine, and ziprasidone. No significant differences in efficacy between AAPs were found, with the exception of clozapine and ziprasidone. Clozapine demonstrated superior efficacy in treatment-resistant patients with EOS, whereas ziprasidone failed to demonstrate efficacy in the treatment of EOS. Our review also focuses on the onset of action and weight gain associated with AAPs. The data on onset of action of AAPs in pediatric psychiatry are scanty and inconsistent. Olanzapine appears to cause the most significant weight gain in patients with EOS, while ziprasidone and aripiprazole seem to cause the least.

QTc interval prolongation and torsade de pointes associated with second-generation antipsychotics and antidepressants: a comprehensive review

We comprehensively reviewed published literature to determine whether it supported the link between corrected QT (QTc) interval prolongation and torsade de pointes (TdP) for the 11 second-generation antipsychotics and seven second-generation antidepressants commonly implicated in these complications. Using PubMed and EMBASE, we identified four thorough QT studies (one each for iloperidone, ziprasidone, citalopram, and escitalopram), 40 studies specifically designed to assess QTc interval prolongation or TdP, 58 publications based on data from efficacy and safety trials, 18 toxicology studies, and 102 case reports. Thorough QT studies, QTc prolongation-specific studies, and studies based on efficacy and safety trials did not link drug-associated QTc interval prolongation with TdP. They only showed that the drugs reviewed caused varying degrees of QTc interval prolongation, and even that information was not clear and consistent enough to stratify individual drugs for this risk. The few toxicology studies provided valuable information but their findings are pertinent only to situations of drug overdose. Case reports were most informative about the drug-QTc interval prolongation-TdP link. At least one additional well established risk factor for QTc prolongation was present in 92.2 % of case reports. Of the 28 cases of TdP, six (21.4 %) experienced it with QTc interval <500 ms; 75 % of TdP cases occurred at therapeutic doses. There is little evidence that drug-associated QTc interval prolongation by itself is sufficient to predict TdP. Future research needs to improve its precision and broaden its scope to better understand the factors that facilitate or attenuate progression of drug-associated QTc interval prolongation to TdP.

The effects of novel and newly approved antipsychotics on serum prolactin levels: a comprehensive review

Since the 1970s, clinicians have increasingly become more familiar with hyperprolactinemia (HPRL) as a common adverse effect of antipsychotic medication, which remains the cornerstone of pharmacological treatment for patients with schizophrenia. Although treatment with second-generation antipsychotics (SGAs) as a group is, compared with use of the first-generation antipsychotics, associated with lower prolactin (PRL) plasma levels, the detailed effects on plasma PRL levels for each of these compounds in reports often remain incomplete or inaccurate. Moreover, at this moment, no review has been published about the effect of the newly approved antipsychotics asenapine, iloperidone and lurasidone on PRL levels. The objective of this review is to describe PRL physiology; PRL measurement; diagnosis, causes, consequences and mechanisms of HPRL; incidence figures of (new-onset) HPRL with SGAs and newly approved antipsychotics in adolescent and adult patients; and revisit lingering questions regarding this hormone. A literature search, using the MEDLINE database (1966-December 2013), was conducted to identify relevant publications to report on the state of the art of HPRL and to summarize the available evidence with respect to the propensity of the SGAs and the newly approved antipsychotics to elevate PRL levels. Our review shows that although HPRL usually is defined as a sustained level of PRL above the laboratory upper limit of normal, limit values show some degree of variability in clinical reports, making the interpretation and comparison of data across studies difficult. Moreover, many reports do not provide much or any data detailing the measurement of PRL. Although the highest rates of HPRL are consistently reported in association with amisulpride, risperidone and paliperidone, while aripiprazole and quetiapine have the most favorable profile with respect to this outcome, all SGAs can induce PRL elevations, especially at the beginning of treatment, and have the potential to cause new-onset HPRL. Considering the PRL-elevating propensity of the newly approved antipsychotics, evidence seems to indicate these agents have a PRL profile comparable to that of clozapine (asenapine and iloperidone), ziprasidone and olanzapine (lurasidone). PRL elevations with antipsychotic medication generally are dose dependant. However, antipsychotics having a high potential for PRL elevation (amisulpride, risperidone and paliperidone) can have a profound impact on PRL levels even at relatively low doses, while PRL levels with antipsychotics having a minimal effect on PRL, in most cases, can remain unchanged (quetiapine) or reduce (aripiprazole) over all dosages. Although tolerance and decreases in PRL values after long-term administration of PRL-elevating antipsychotics can occur, the elevations, in most cases, remain above the upper limit of normal. PRL profiles of antipsychotics in children and adolescents seem to be the same as in adults. The hyperprolactinemic effects of antipsychotic medication are mostly correlated with their affinity for dopamine D2 receptors at the level of the anterior pituitary lactotrophs (and probably other neurotransmitter mechanisms) and their blood-brain barrier penetrating capability. Even though antipsychotics are the most common cause of pharmacologically induced HPRL, recent research has shown that HPRL can be pre-existing in a substantial portion of antipsychotic-naïve patients with first-episode psychosis or at-risk mental state.

Efficacy of olanzapine in comparison with clozapine for treatment-resistant schizophrenia: evidence from a systematic review and meta-analyses

INTRODUCTION

Clozapine is considered the gold standard for the treatment of patients with treatment-resistant schizophrenia (TRS); however, randomized controlled trials (RCT) of olanzapine showed efficacy similar to clozapine in patients with TRS.

METHODS

A systematic review was conducted comparing clozapine with olanzapine in patients with TRS. Meta-analyses were performed for single outcome measures. Response to treatment was measured by the percentage of responders, or mean change or endpoint values of psychotic symptoms scales. Effect sizes were shown as relative risks (RR), or standardized mean differences, with 95% confidence intervals.

FINDINGS

Seven RCT were included, comprising 648 patients. Five meta-analyses were performed. Olanzapine and clozapine had similar effects on dropout rates (RR = 0.93, CI95% = 0.77-1.12), PANSS total endpoints (SMD = 0.21, CI95% = -0.04-0.46), and PANSS total mean changes (SMD = 0.08, CI95% = -0.01-0.027). Clozapine was superior to olanzapine for PANSS positive (SMD = 0.51, CI95% = 0.17-0.86) and negative (SMD = 0.50, CI95% = 0.16-0.85) subscales. There was a trend toward high doses of olanzapine producing higher effect sizes for this drug.

CONCLUSIONS

The results of this study suggest that clozapine is significantly more efficacious than olanzapine in improving positive and negative symptoms in TRS patients.

Evidence review and clinical guidance for the use of ziprasidone in Canada

While indicated for schizophrenia and acute mania, ziprasidone's evidence base and use in clinical practice extends beyond these regulatory approvals. We, an invited panel of experts led by a working group of 3, critically examined the evidence and our collective experience regarding the effectiveness, tolerability and safety of ziprasidone across its clinical uses. There was no opportunity for manufacturer input into the content of the review. As anticipated, ziprasidone was found to be effective for its indicated uses, although its utility in mania and mixed states lacked comparative data. Beyond these uses, the available data were either unimpressive or were lacking. An attractive characteristic is its neutral effect on weight thereby providing patients with a non-obesogenic long-term treatment option. Key challenges in practice include the need for dosing on a full stomach and managing its early onset adverse effect of restlessness. Addressing these issues are critical to its long-term success.

Clozapine: balancing safety with superior antipsychotic efficacy

Clozapine is often referred to as the gold standard for the treatment of schizophrenia and yet has also been described as the most underutilized treatment for schizophrenia supported by solid evidence-based medicine. In 2008, it was used to treat only 4.4% of patients with schizophrenia in the U.S., which is ~10-20% of those with approved indications for clozapine for which there is no alternative of equal efficacy. Its use is much higher in Scandinavian countries and China. The primary indications for clozapine are: 1) treatment-resistant schizophrenia or schizoaffective disorder, defined as persistent moderate to severe delusions or hallucinations despite two or more clinical trials with other antipsychotic drugs; and, 2) patients with schizophrenia or schizoaffective disorder who are at high risk for suicide. Concerns over a number of safety considerations are responsible for much of the underutilization of clozapine: 1) agranulocytosis; 2) metabolic side effects; and, 3) myocarditis. These side effects can be detected, prevented, minimized and treated, but there will be a very small number of fatalities. Nevertheless, clozapine has been found in two large epidemiologic studies to have the lowest mortality of any antipsychotic drug, mainly due to its very large effect to reduce the risk for suicide. Other reasons for limited use of clozapine include the extra effort entailed in monitoring white blood cell counts to detect granulocytopenia or agranulocytosis and, possibly, minimal efforts to market it now that it is largely generic. Awareness of the benefits and risks of clozapine is essential for increasing the use of this lifesaving agent.

A quantitative review of the profile and time course of symptom change in schizophrenia treated with clozapine

Contemporary analyses demonstrate an early response to antipsychotic treatment in non-refractory schizophrenia. The profile of response to clozapine is unknown. We used meta-analytic and statistical procedures to examine the response profile to clozapine. We identified 19 unique, randomized, double-blind controlled clinical trials with suitable time course data, representing 1745 subjects. Individual subject data were available for 419 subjects, obtained from two industry-sponsored trials. Symptom severity scores from the BPRS or the PANSS were entered into regression analyses to estimate linear and quadratic coefficients of the rate of change of symptom severity over 4 weeks. Both linear and quadratic regression coefficients for clozapine, and for comparator antipsychotics differed significantly from zero (p ≤ 0.001), indicating early response profiles. Compared with other antipsychotic arms, for clozapine the treatment response was greater (d = -0.578, p = 0.021), and the linear coefficient was steeper (d = -0.502, p = 0.042); the quadratic coefficients indicating attenuation did not differ. Analyses of 6-week data and individual subject data from non-refractory and refractory trials were consistent with the primary findings. Somewhat surprisingly, clozapine shows an early response profile, similar in pattern but somewhat larger in magnitude than other antipsychotic drugs.

Who's left? Symptoms of schizophrenia that predict clinical trial dropout

A significant proportion of subjects drop out of medium to long-term clinical studies prior to trial completion. This may bias reported study outcomes and reduce the statistical power of analyses. There is therefore a need for researchers to better understand the characteristics of dropout populations to increase completion rates. Data from a set of participants recruited as part of a 24-week placebo-controlled trial were used to determine the relationship between the five Lindenmayer factors of positive, negative, cognitive, anxiety/depression and excitement symptoms and dropout at trial completion. Results indicated that the rate of trial dropout was significantly predicted by scores on the negative Lindenmayer factor (X² (6, N = 126) = 15.60, p < .05). By trial completion, participants with 'high' negative Lindenmayer scores dropped out at a rate of 64%, whereas 'medium' and 'low' groups dropped out at 43% and 30%, respectively. No other relationship between symptom severity scores and dropout across the remaining Lindenmayer factors was found. These findings reflect important considerations for the future design of clinical trials involving people with schizophrenia and may also provide clues into treatment compliance issues more generally.

Effects on prolongation of Bazett's corrected QT interval of seven second-generation antipsychotics in the treatment of schizophrenia: a meta-analysis

The use of second-generation antipsychotics (SGAs) for the treatment of schizophrenia has surged worldwide. Amisulpride, aripiprazole, olanzapine, quetiapine, risperidone, sertindole and ziprasidone have now been commonly prescribed. Their effects on QT interval differ but evidence remains sparse and mostly inconclusive. Since prolongation of heart-rate corrected QT interval has been implicated as an useful surrogate marker to predict drug-related cardiac mortality and pro-arrhythmic potentials, it is timely and necessary to compare the effects of Bazett's corrected QT interval (QT(Bc)) prolongation for the commonly prescribed SGAs. A meta-analysis was conducted according to suggestions by the Quality of Reporting of Meta-analysis group with literature identified using various databases and augmented with hand-searching to assess the magnitude and risk on QT(Bc) prolongation by these seven SGAs for treatments in adult subjects with schizophrenia. Because of incomplete QT(Bc) data reporting, quetiapine could not be assessed by the meta-analytical approach in this study. Aripiprazole was the only SGA associated with both statistically significant lower risk and mean change in QT(Bc), with sertindole giving a statistically significant worsening effect on mean QT(Bc). Other analyses did not demonstrate any statistically significant pooled effects for the studied SGAs, neither on the magnitude over mean or mean change, nor the risk on QT(Bc) prolongation.

Risk of osteoporosis and fracture incidence in patients on antipsychotic medication

INTRODUCTION

In patients suffering from schizophrenia and bipolar disorder, antipsychotics are the mainstay of treatment worldwide. By blocking D(2) brain mesolimbic receptors, antipsychotics are believed to reduce and control psychotic experiences, but recent evidence has suggested that they may also have adverse effects on bone mineral architecture and fracture incidence.

AREAS COVERED

This study reviews current literature surrounding the use of antipsychotics and their effects on bone homeostasis. The primary medical search engines used for the study are Ovid MEDLINE (1950 - April 2010), EMBASE (1988 - April 2010) and PsychINFO (1987 - April 2010) databases.

EXPERT OPINION

Typical antipsychotics, in addition to the atypical antipsychotics risperidone and amisulpride, have been shown to increase serum prolactin levels in in vivo human studies. Results from animal and human in vitro and in vivo studies have demonstrated that high concentrations of prolactin have been shown to adversely affect bone cell metabolism and accelerate the rate bone mineral density loss, thereby increasing fracture risk. Increasing awareness of the side effect profile of antipsychotic medications on bone metabolism may prompt clinicians to screen patients at high risk of antipsychotic-induced osteoporosis and provide treatment, which may reduce the incidence of potentially avoidable fractures.

Should the PANSS be rescaled?

The design of the Positive and Negative Syndrome Scale (PANSS) with item levels ranging from 1 to 7 leads to the trivial result that the 30-item scale's zero level (no symptoms) is 30. This causes serious problems when ratios are calculated which always implicitly depend on a natural zero point (equals 0). Recent publications concerning efficacy of antipsychotics correctly suggest a subtraction of 30 points to every PANSS before calculating percent change (PC). Nevertheless, the traditional approach using uncorrected scores is still in common practice. This analysis aims to clarify which approach is the most appropriate from a statistical perspective.For analysis, data from a naturalistic study on 400 patients with a schizophrenic spectrum disorder and simulated data sets were used. While calculations concerning absolute score values and their differences are not affected, considerable problems arise in calculations of PC and related response criteria. Even significance levels of estimated treatment effects change, depending on the structure of the data (eg, baseline symptom severity). Using a PANSS version with items ranging from 0 to 6 would avoid such often neglected pitfalls.

Ziprasidone versus other atypical antipsychotics for schizophrenia

BACKGROUND

In many countries of the industrialised world second generation ('atypical') antipsychotics have become the first line drug treatment for people with schizophrenia. The question as to whether, and if so how much, the effects of the various new generation antipsychotics differ is a matter of debate. In this review we examined how the efficacy and tolerability of ziprasidone differs from that of other second generation antipsychotics.

OBJECTIVES

To evaluate the effects of ziprasidone compared with other atypical antipsychotics for people with schizophrenia and schizophrenia-like psychoses.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group Specialised Register (April 2007) and references of all identified studies for further trial citations. We contacted pharmaceutical companies and authors of trials for additional information.

SELECTION CRITERIA

We included all randomised, at least single-blind, controlled trials comparing oral ziprasidone with oral forms of amisulpride, aripiprazole, clozapine, olanzapine, quetiapine, risperidone or zotepine in people with schizophrenia or schizophrenia-like psychoses.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For continuous data, we calculated weighted mean differences (MD) for dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a random-effects model. We calculated numbers needed to treat/harm (NNT/NNH) where appropriate.

MAIN RESULTS

The review currently includes nine randomised controlled trials (RCTs) with 3361 participants. The overall rate of premature study discontinuation was very high (59.1%). Data for the comparisons of ziprasidone with amisulpride, clozapine, olanzapine, quetiapine and risperidone were available. Ziprasidone was a less acceptable treatment than olanzapine (leaving the studies early for any reason: 5 RCTs, n=1937, RR 1.26 CI 1.18 to 1.35, NNH 7 CI 5 to 10) and risperidone (3 RCTs, n=1029, RR 1.11 CI 1.02 to 1.20, NNH 14 CI 8 to 50), but not than the other second generation antipsychotic drugs. Ziprasidone was less efficacious than amisulpride (leaving the study early due to inefficacy: 1 RCT, n=123, RR 4.72 CI 1.06 to 20.98, NNH 8 CI 5 to 50) olanzapine (PANSS total score: 4 RCTs, n=1291, MD 8.32 CI 5.64 to 10.99) and risperidone (PANSS total score: 3 RCTs, n=1016, MD 3.91 CI 0.27 to 7.55). Based on limited data there were no significant differences in tolerability between ziprasidone and amisulpride or clozapine. Ziprasidone produced less weight gain than olanzapine (5 RCTs, n=1659, MD -3.82 CI -4.69 to -2.96), quetiapine (2 RCTs, n=754, RR 0.45 CI 0.28 to 0.74) or risperidone (3 RCTs, n=1063, RR 0.49 CI 0.33 to 0.74). It was associated with less cholesterol increase than olanzapine, quetiapine and risperidone. Conversely ziprasidone produced slightly more extrapyramidal side-effects than olanzapine (4 RCTs, n=1732, RR 1.43 CI 1.03 to 1.99, NNH not estimable) and more prolactin increase than quetiapine (2 RCTs, n=754, MD 4.77 CI 1.37 to 8.16), but less movement disorders (2 RCTs, n=822, RR 0.70 CI 0.51 to 0.97, NNT not estimable) and less prolactin increase (2 RCTs, n=767, MD -21.97 CI -27.34 to -16.60) than risperidone.

AUTHORS' CONCLUSIONS

Ziprasidone may be a slightly less efficacious antipsychotic drug than amisulpride, olanzapine and risperidone. Its main advantage is the low propensity to induce weight gain and associated adverse effects. However, the high overall rate of participants leaving the studies early limits the validity of any findings.