Background: In many countries of the industrialised world, second generation (atypical) antipsychotic drugs have become first line treatment for people with schizophrenia. The question as to whether the effects of various second generation antipsychotic drugs differ is a matter of debate. In this review we examined how the efficacy and tolerability of zotepine differs from that of other second generation antipsychotic drugs.
Objectives: To evaluate the effects of zotepine compared with other second generation antipsychotic drugs for people with schizophrenia and schizophrenia-like psychoses.
Search strategy: We searched the Cochrane Schizophrenia Group Trials Register (April 2007) which is based on regular searches of BIOSIS, CENTRAL CINAHL, EMBASE, MEDLINE and PsycINFO.
Selection criteria: We included all randomised trials comparing oral zotepine with oral forms of amisulpride, aripiprazole, clozapine, olanzapine, risperidone, sertindole or ziprasidone in people with schizophrenia or schizophrenia-like psychoses.
Data collection and analysis: 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 (MD) again based on a random effects model.
Main results: The review currently includes data from two short term, ill reported trials (total n=109). Both studies compared zotepine with clozapine. 34% of people left early but there was no significant difference between groups. Zotepine was less effective than clozapine (no clinically significant response: n=59, 1 RCT, RR 8.23 CI 1.14 to 59.17, NNH 3 CI 2 to 8; average score (BPRS total) at endpoint (n=59, 1 RCT, MD 6.00 CI 2.17 to 9.83). Zotepine induced more movement disorders than clozapine (use of antiparkinson medication: n=59, 1 RCT, RR 18.75 CI 1.17 to 301.08, NNH 3 CI 2 to 5) and higher prolactin levels (n=59, 1 RCT, MD 33.40 CI 14.87 to 51.93). Data on important other outcomes such as other adverse events, service use or satisfaction with care were not available.
Authors' conclusions: Zotepine may be less effective than clozapine and associated with more movement disorders and higher prolactin levels, but the evidence base is too small and prone to bias, making any practical recommendations impossible. There is no randomised evidence on the effects of zotepine compared to second generation antipsychotic drugs other than clozapine. More studies are possible to justify.