title: Quetiapine versus other atypical antipsychotics for schizophrenia.
abstract: BACKGROUND
  In many countries of the industrialised world second generation ('atypical') antipsychotic drugs have become the first line drug treatment for people with schizophrenia. It is not clear how the effects of the various second generation antipsychotic drugs differ.
  
  
  OBJECTIVE
  To evaluate the effects of quetiapine compared with other second generation antipsychotic drugs for people with schizophrenia and schizophrenia-like psychosis.
  
  
  METHODS
  We searched the Cochrane Schizophrenia Group Trials Register (April 2007), inspected references of all identified studies, and contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information.
  
  
  METHODS
  We included all randomised control trials comparing oral quetiapine with oral forms of amisulpride, aripiprazole, clozapine, olanzapine, risperidone, sertindole, ziprasidone or zotepine in people with schizophrenia or schizophrenia-like psychosis.
  
  
  METHODS
  We extracted data independently. 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. For continuous data, we calculated weighted mean differences (WMD) again based on a random-effects model.
  
  
  RESULTS
  The review currently includes 21 randomised control trials (RCTs) with 4101 participants. These trials provided data on four comparisons - quetiapine versus clozapine, olanzapine, risperidone or ziprasidone.A major limitation to all findings is the high number of participants leaving studies prematurely (57.6%) and the substantial risk of biases in studies. Efficacy data favoured olanzapine and risperidone compared with quetiapine (PANSS total score versus olanzapine:10 RCTs, n=1449, WMD 3.66 CI 1.93 to 5.39; versus risperidone: 9 RCTs, n=1953, WMD 3.09 CI 1.01 to 5.16), but clinical meaning is unclear. There were no clear mental state differences when quetiapine was compared with clozapine or ziprasidone.Compared with olanzapine, quetiapine produced slightly fewer movement disorders (6 RCTs, n=1090, RR use of antiparkinson medication 0.49 CI 0.3 to 0.79, NNH 25 CI 14 to 100) and less weight gain (7 RCTs, n=1173, WMD -2.81 CI -4.38 to -1.24) and glucose elevation, but more QTc prolongation (3 RCTs, n=643, WMD 4.81 CI 0.34 to 9.28). Compared with risperidone, quetiapine induced slightly fewer movement disorders (6 RCTs, n=1715, RR use of antiparkinson medication 0.5 CI 0.3 to 0.86, NNH 20 CI 10 to 100), less prolactin increase (6 RCTs, n=1731, WMD -35.28 CI -44.36 to -26.19) and some related adverse effects, but more cholesterol increase (5 RCTs, n=1433, WMD 8.61 CI 4.66 to 12.56). Compared with ziprasidone, quetiapine induced slightly fewer extrapyramidal adverse effects (1 RCT, n=522, RR use of antiparkinson medication 0.43 CI 0.2 to 0.93, NNH not estimable) and prolactin increase. On the other hand quetiapine was more sedating and led to more weight gain (2 RCTs, n=754, RR 2.22 CI 1.35 to 3.63, NNH 13 CI 8 to 33) and cholesterol increase than ziprasidone.
  
  
  CONCLUSIONS
  Best available evidence from trials suggests that most people who start quetiapine stop taking it within a few weeks. Comparisons with amisulpride, aripiprazole, sertindole and zotepine do not exist. Most data that has been reported within existing comparisons are of very limited value because of assumptions and biases within them. There is much scope for further research into the effects of this widely used drug.
authors.affiliation: Klinik und Poliklinik für Psychiatrie und Psychotherapie, Technische Universität München Klinikum rechts der Isar, Moehlstrasse 26, München, Germany, 81675.
authors.forename: Katja
authors.initials: K
authors.lastname: Komossa
authors.forename: Christine
authors.initials: C
authors.lastname: Rummel-Kluge
authors.forename: Franziska
authors.initials: F
authors.lastname: Schmid
authors.forename: Heike
authors.initials: H
authors.lastname: Hunger
authors.forename: Sandra
authors.initials: S
authors.lastname: Schwarz
authors.forename: Manit
authors.initials: M
authors.lastname: Srisurapanont
authors.forename: Werner
authors.initials: W
authors.lastname: Kissling
authors.forename: Stefan
authors.initials: S
authors.lastname: Leucht
mesh_terms: D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000009:adverse effects / Q000627:therapeutic use; D003024:Clozapine / Q000009:adverse effects / Q000627:therapeutic use; D003987:Dibenzothiazepines / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D000077152:Olanzapine; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use; D000069348:Quetiapine Fumarate; D016032:Randomized Controlled Trials as Topic; D018967:Risperidone / Q000009:adverse effects / Q000627:therapeutic use; D012559:Schizophrenia / Q000188:drug therapy*; D013844:Thiazoles / Q000009:adverse effects / Q000627:therapeutic use; D016903:Drug Monitoring
chemical_list: D014150:Antipsychotic Agents; D003987:Dibenzothiazepines; D010879:Piperazines; D013844:Thiazoles; D001569:Benzodiazepines; D000069348:Quetiapine Fumarate; C092292:ziprasidone; D003024:Clozapine; D018967:Risperidone; D000077152:Olanzapine