Tags

Type your tag names separated by a space and hit enter

Olanzapine for schizophrenia.

Abstract

BACKGROUND

Olanzapine is an atypical antipsychotic reported to be effective without producing disabling extrapyramidal adverse effects associated with older, typical antipsychotic drugs.

OBJECTIVES

To determine the clinical effects and safety of olanzapine compared with placebo, typical and other atypical antipsychotic drugs for schizophrenia and schizophreniform psychoses.

SEARCH STRATEGY

We updated the first search [Biological Abstracts (1980-1999), The Cochrane Library (Issue 2, 1999), EMBASE (1980-1999), MEDLINE (1966-1999), PsycLIT (1974-1999) and The Cochrane Schizophrenia Group's Register (October 2000)] in October 2004 using the Cochrane Schizophrenia's Group's register of trials. We also searched references of all included studies for further trials, and contacted relevant pharmaceutical companies and authors.

SELECTION CRITERIA

We included all randomised clinical trials comparing olanzapine with placebo or any antipsychotic treatment for people with schizophrenia or schizophreniform psychoses.

DATA COLLECTION AND ANALYSIS

We independently extracted data and, for homogeneous dichotomous data, calculated the random effects relative risk (RR), the 95% confidence intervals (CI) and the number needed to treat (NNT) on an intention-to-treat basis. For continuous data we calculated weighted mean differences.

MAIN RESULTS

Fifty five trials are included (total n>10000 people with schizophrenia). Attrition from olanzapine versus placebo studies was >50% by six weeks, leaving interpretation of results problematic. Olanzapine appeared superior to placebo at six weeks for the outcome of 'no important clinical response' (any dose, 2 RCTs n=418, RR 0.88 CI 0.8 to 0.1, NNT 8 CI 5 to 27). Although dizziness and dry mouth were reported more frequently in the olanzapine-treated group, this did not reach statistical significance. The olanzapine group gained more weight. When compared with typical antipsychotic drugs, data from several small trials are incomplete. With high attrition in both groups (14 RCTs, n=3344, 38% attrition by six weeks, RR 0.81 CI 0.65 to 1.02) the assumptions included in all data are considerable. For the short term outcome of 'no important clinical response', olanzapine seems as effective as typical antipsychotics (4 RCTs, n=2778, RR 0.90 CI 0.76 to 1.06). People allocated olanzapine experienced fewer extrapyramidal adverse effects than those given typical antipsychotics. Weight change data for the short term are not statistically significant but results between three to 12 months suggest a clinically important average gain of four kilograms for people given olanzapine (4 RCTs, n=186, WMD 4.62, CI 0.6 to 8.64). Twenty three percent of people in trials of olanzapine and other atypical drugs left by eight weeks; 48% by three to12 months (11 RCTs, n=1847, RR 0.91 CI 0.82 to 1.00). There is little to choose between the atypicals, although olanzapine may cause fewer extrapyramidal adverse effects than other drugs in this category. Olanzapine produces more weight gain than other atypicals with some differences reaching conventional levels of statistical significance (1 RCT, n=980, RR gain at 2 years 1.73 CI 1.49 to 2.00, NNH 5 CI 4 to 7). There are very few data for people with first episode illness (1 RCT, duration 6 weeks, n=42). For people with treatment-resistant illness there were no clear differences between olanzapine and clozapine (4 RCTs, n=457).

AUTHORS' CONCLUSIONS

The large proportion of participants leaving studies early in these trials makes it difficult to draw firm conclusions on olanzapine's clinical effects. For people with schizophrenia it may offer antipsychotic efficacy with fewer extrapyramidal adverse effects than typical drugs, but more weight gain. There is a need for further large, long-term randomised trials with more comprehensive data.

Authors+Show Affiliations

Smyth Division, St Andrew's Hospital, Billing Rd, Northampton, Northamptonshire, UK, NN1 5DG. lornaduggan@yahoo.co.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Meta-Analysis
Review
Systematic Review

Language

eng

PubMed ID

15846619

Citation

Duggan, L, et al. "Olanzapine for Schizophrenia." The Cochrane Database of Systematic Reviews, 2005, p. CD001359.
Duggan L, Fenton M, Rathbone J, et al. Olanzapine for schizophrenia. Cochrane Database Syst Rev. 2005.
Duggan, L., Fenton, M., Rathbone, J., Dardennes, R., El-Dosoky, A., & Indran, S. (2005). Olanzapine for schizophrenia. The Cochrane Database of Systematic Reviews, (2), CD001359.
Duggan L, et al. Olanzapine for Schizophrenia. Cochrane Database Syst Rev. 2005 Apr 18;(2)CD001359. PubMed PMID: 15846619.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Olanzapine for schizophrenia. AU - Duggan,L, AU - Fenton,M, AU - Rathbone,J, AU - Dardennes,R, AU - El-Dosoky,A, AU - Indran,S, Y1 - 2005/04/18/ PY - 2005/4/23/pubmed PY - 2005/7/20/medline PY - 2005/4/23/entrez SP - CD001359 EP - CD001359 JF - The Cochrane database of systematic reviews JO - Cochrane Database Syst Rev IS - 2 N2 - BACKGROUND: Olanzapine is an atypical antipsychotic reported to be effective without producing disabling extrapyramidal adverse effects associated with older, typical antipsychotic drugs. OBJECTIVES: To determine the clinical effects and safety of olanzapine compared with placebo, typical and other atypical antipsychotic drugs for schizophrenia and schizophreniform psychoses. SEARCH STRATEGY: We updated the first search [Biological Abstracts (1980-1999), The Cochrane Library (Issue 2, 1999), EMBASE (1980-1999), MEDLINE (1966-1999), PsycLIT (1974-1999) and The Cochrane Schizophrenia Group's Register (October 2000)] in October 2004 using the Cochrane Schizophrenia's Group's register of trials. We also searched references of all included studies for further trials, and contacted relevant pharmaceutical companies and authors. SELECTION CRITERIA: We included all randomised clinical trials comparing olanzapine with placebo or any antipsychotic treatment for people with schizophrenia or schizophreniform psychoses. DATA COLLECTION AND ANALYSIS: We independently extracted data and, for homogeneous dichotomous data, calculated the random effects relative risk (RR), the 95% confidence intervals (CI) and the number needed to treat (NNT) on an intention-to-treat basis. For continuous data we calculated weighted mean differences. MAIN RESULTS: Fifty five trials are included (total n>10000 people with schizophrenia). Attrition from olanzapine versus placebo studies was >50% by six weeks, leaving interpretation of results problematic. Olanzapine appeared superior to placebo at six weeks for the outcome of 'no important clinical response' (any dose, 2 RCTs n=418, RR 0.88 CI 0.8 to 0.1, NNT 8 CI 5 to 27). Although dizziness and dry mouth were reported more frequently in the olanzapine-treated group, this did not reach statistical significance. The olanzapine group gained more weight. When compared with typical antipsychotic drugs, data from several small trials are incomplete. With high attrition in both groups (14 RCTs, n=3344, 38% attrition by six weeks, RR 0.81 CI 0.65 to 1.02) the assumptions included in all data are considerable. For the short term outcome of 'no important clinical response', olanzapine seems as effective as typical antipsychotics (4 RCTs, n=2778, RR 0.90 CI 0.76 to 1.06). People allocated olanzapine experienced fewer extrapyramidal adverse effects than those given typical antipsychotics. Weight change data for the short term are not statistically significant but results between three to 12 months suggest a clinically important average gain of four kilograms for people given olanzapine (4 RCTs, n=186, WMD 4.62, CI 0.6 to 8.64). Twenty three percent of people in trials of olanzapine and other atypical drugs left by eight weeks; 48% by three to12 months (11 RCTs, n=1847, RR 0.91 CI 0.82 to 1.00). There is little to choose between the atypicals, although olanzapine may cause fewer extrapyramidal adverse effects than other drugs in this category. Olanzapine produces more weight gain than other atypicals with some differences reaching conventional levels of statistical significance (1 RCT, n=980, RR gain at 2 years 1.73 CI 1.49 to 2.00, NNH 5 CI 4 to 7). There are very few data for people with first episode illness (1 RCT, duration 6 weeks, n=42). For people with treatment-resistant illness there were no clear differences between olanzapine and clozapine (4 RCTs, n=457). AUTHORS' CONCLUSIONS: The large proportion of participants leaving studies early in these trials makes it difficult to draw firm conclusions on olanzapine's clinical effects. For people with schizophrenia it may offer antipsychotic efficacy with fewer extrapyramidal adverse effects than typical drugs, but more weight gain. There is a need for further large, long-term randomised trials with more comprehensive data. SN - 1469-493X UR - https://www.unboundmedicine.com/medline/citation/15846619/Olanzapine_for_schizophrenia_ DB - PRIME DP - Unbound Medicine ER -