Switching from risperidone to olanzapine in a one-year, randomized, open-label effectiveness study of schizophrenia

Objective: Switching medications is common in the treatment of schizophrenia. This study examines the effectiveness of olanzapine therapy following a clinically warranted switch from risperidone during treatment of patients with schizophrenia. Research design and methods: This post-hoc analysis used data from the risperidone arm of a randomized, open-label, 1-year study of patients with schizophrenia. Study protocol permitted antipsychotic switching when clinically warranted, and outcomes were assessed with standard psychiatric measures. Statistical analyses assessed changes from pre- to post-medication switch and endpoint comparisons between patients switched from risperidone to olanzapine and patients continued on risperidone. Results: Most patients who switched from risperidone switched to olanzapine (43/60; 71.7%). Average duration of risperidone treatment prior to switching was 86 days (mean modal dose 4.0 mg/day). Most switchers (86%) completed the 1-year study on olanzapine (average duration 241 days; mean modal dose 12.0mg/day). Following switch to olanzapine, patients experienced significant improvements on clinical (Brief Psychiatric Rating Scale) and social (Quality of Life Inventory) parameters, with similar proportions of patients achieving remission status at endpoint compared with risperidone patients not requiring medication switch (41.9 vs. 35.5%). Mean weight gain for switchers was approximately 0.4 kg while on risperidone (average treatment duration < 3 months) and 2.4 kg on olanzapine (average treatment duration approximately 8 months). Conclusions: This study suggests that olanzapine is an effective treatment option for schizophrenia patients requiring a switch from risperidone. Given the small sample size and lack of a comparative group, one cannot determine if other medication options would have been as effective as the switch to olanzapine. Thus, further research is warranted.