Clinical Trials of Risperidone in the Patients with Schizophrenia: Comparison with Other Antipsychotics

Kim, Young Hoon

Abstract

Several double-blind comparative studies and two combined analysis of double-blind studies comparing the safety, tolerability and clinical efficacy of risperidone with those of haloperidol and other atypical antipsychotics were reviewed. Risperidone was more efficious than haloperidol for reducing a range of symptoms of schizophrenia. A favorable extrapyramidal symptom (EPS) profile was also obtained at doses of less than 8 mg/day of risperidone comparing with haloperidol. Five double-blind, head to head comparison studies between risperidone and other atypical antipsychotics were published till now. Two compared the safety and efficacy of risperidone with those of clozapine in chronic schizophrenia, and the other two compared the safety and efficacy of risperidone with those of olanzapine in acute schizophrenia, schizoaffective and schzophreniform disorders, and the last one compared the safety and efficacy of risperidone with those of amisulpride in schizophrenia. While relatively few comparative studies of atypicals have been conducted, it is generally accepted that the efficacy is similar among the atypical antipsychotics including risperidone. Superiority of an atypical agent over the other in the effectiveness against one or more symptom domains of schizophrenia were demonstrated in some studies, but their evidences were occasionally lack of statistical confidences. In conclusions, the atypical antipsychotics including risperidone provide a wide therapeutic base, with demonstrated efficacy against the negative symptoms, affective symptoms, and cognitive deficit associated with schizophrenia. Atypical antipsychotics have improved tolerability, particularly with regard to EPSs. but the tolerability profiles of the atypical antipsychotics differ from one another in a number of respects. Reduction of symptoms without clinically important adverse events such as hyperprolactinemia, weight gain and new onset of diabetes, prolongation of cardiac QTc interval is a major concern with the use of atypical antipsychotics.