Metabolic findings from the CATIE trial and their relation to tolerability

The overall effectiveness of antipsychotics for the management of schizophrenia is restricted by their side-effect profiles, particularly over an extended treatment period. Intolerable side effects can reduce patient adherence to medication and often lead to treatment discontinuation. Some side effects that result from antipsychotic use are precursors to the metabolic syndrome, which is prevalent among individuals with schizophrenia and represents a significant source of cardiovascular risk. The Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) schizophrenia study assessed the efficacy of the atypical antipsychotics olanzapine, quetiapine, risperidone, and ziprasidone relative to the conventional drug perphenazine. Additional assessments included the metabolic effects of these agents in patients with schizophrenia and the incidence of negative side effects. No significant differences were found between treatment groups for time to discontinuation due to intolerability, but the rates of side effects significantly differed (P=.04). For metabolic parameters, olanzapine was associated with greater and significant adverse effects on weight, lipids, and glucose metabolism versus the other antipsychotics tested. The CATIE results show that important distinctions exist among currently available atypical antipsychotics. Physicians should be aware of the propensity of these drugs to increase the risks of cardiovascular disease and diabetes in treated patients and tailor individual treatment decisions accordingly. This article highlights the metabolic findings from the CATIE schizophrenia study, and explores the differences shown by atypical antipsychotics, with regard to metabolic side effects that increase cardiovascular risk.