Effectiveness of Switching Antipsychotic Medications

Objective: Changing antipsychotics is common despite the dearth of information on risks and benefits associated with medication changes. The authors examined phase 1 findings from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study to explore whether it was more advantageous to continue taking the medication being received at baseline or to switch to a different antipsychotic. Method: First, for patients randomly assigned to treatment with olanzapine (N=314) or risperidone (N=321), the authors assessed the impact of being assigned to stay with the medication they were receiving at entry into the study versus being assigned to switch to these medications from a different antipsychotic. Second, for patients whose baseline antipsychotic was olanzapine (N=319), risperidone (N=271), or quetiapine (N=94), the authors examined the impact of being randomly assigned to stay with the same antipsychotic versus switch. Finally, the authors assessed the impact of removing the data of 209 patients whose random assignment was to stay with their baseline antipsychotic. The authors followed analysis strategies for CATIE; primary outcome was time until all-cause treatment discontinuation. Results: Individuals randomly assigned to olanzapine and risperidone who were continuing with their baseline medication had significantly longer times until discontinuation than did those assigned to switch antipsychotics. When these “stayers” were removed, differences seen in the original CATIE phase 1 analyses were attenuated, although the original pattern of results remained. Conclusions: Comparisons of medication effectiveness should take into account whether medications being compared were each newly initiated. Further, unless the clinical situation requires a medication change, prescribers may want to take steps to optimize current medication regimens (e.g., dosage adjustments, behavioral or psychosocial interventions) before switching medications.