A comparison of ziprasidone and risperidone in the long-term treatment of schizophrenia: a 44-week, double-blind, continuation study.

Objective: This randomized, double-blind, multicentre extension study compared the efficacy, tolerability, and safety of ziprasidone and risperidone for schizophrenia or schizoaffective disorder.

Methods: Patients who had responded to treatment for an acute exacerbation of illness in an 8-week study received ziprasidone, 80 to 160 mg/day (n = 62), or risperidone, 6 to 10 mg/day (n = 77), for up to 44 additional weeks. Primary efficacy variables included changes in Positive and Negative Syndrome Scale (PANSS) total score and Clinical Global Impression Severity (CGI-S) score. Tolerability and safety assessments included movement disorders, adverse events, study discontinuation rates, and weight and metabolic parameters.

Results: Both the ziprasidone and risperidone groups showed statistical improvement from baseline in PANSS and CGI-S scores at study end point with no significant differences between treatment groups. More risperidone-treated patients completed the study (41.6%) than ziprasidone-treated patients (33.9%), but the difference was not statistically significant. Ziprasidone-treated patients who completed the study showed greater improvement in depressive symptoms assessed by Montgomery and Asberg Depression Rating Scale than risperidone-treated patients (P < 0.05). Ziprasidone was associated with a more favourable effect on extrapyramidal symptom (EPS) measures and prolactin as well as less weight gain than risperidone. Median dosages were ziprasidone 120 mg/day and risperidone 8 mg/day.

Conclusions: Ziprasidone and risperidone demonstrated similar efficacy during long-term treatment of patients with schizophrenia or schizoaffective disorder. While more subjects on risperidone completed the extension study, ziprasidone was associated with fewer adverse effects on weight, EPS measures, and prolactin than risperidone.