Clozapine and risperidone in chronic schizophrenia: effects on symptoms, parkinsonian side effects, and neuroendocrine response. Risperidone versus clozapine in treatment-resistant chronic schizophrenia: a randomized double-blind study. The Risperidone Study Group. The tolerability and efficacy of the atypical neuroleptic remoxipride compared with clozapine and haloperidol in acute schizophrenia. Risperidone versus clozapine in treatment-resistant schizophrenia: a randomized pilot study.
Clozapine and risperidone were the first two "second-generation" antipsychotic drugs approved for schizophrenia. There is currently little information about their comparative efficacy from head-to-head clinical trials. The purpose of this study was to examine the comparative efficacy of clozapine and risperidone for positive and negative symptoms, depression, parkinsonian side effects, and indexes of neuroendocrine function in schizophrenic patients who met a priori criteria for partial response to traditional neuroleptic agents.
                After a baseline fluphenazine treatment period, 29 patients participated in a 6-week, double-blind, parallel-group comparison of the effects of these agents.
                Clozapine was superior to risperidone for positive symptoms and parkinsonian side effects, but there were no significant differences between the drugs on two measures of negative symptoms, Brief Psychiatric Rating Scale total scores, and depression scores. The clozapine patients, but not the risperidone patients, demonstrated significant reductions from the fluphenazine baseline in positive symptoms, total symptoms, and depression. In addition, clozapine produced fewer effects on plasma prolactin than risperidone or fluphenazine. The mean daily doses during week 6 of the trial were 403.6 mg of clozapine and 5.9 mg of risperidone.
                The findings from this study indicate that these drugs have both important differences and similarities in their comparative efficacy in chronically ill, partially responsive patients with schizophrenia. Further research on second-generation antipsychotic drugs in this patient population that addresses key methodological issues, such as optimal dose and treatment duration, are needed. The purpose of this study was to compare the short-term efficacy and safety of risperidone and clozapine in treatment-resistant chronic schizophrenic patients.
                In a controlled double-blind, multicenter study, 86 inpatients with chronic schizophrenia (DSM-III-R), who were resistant to or intolerant of conventional neuroleptics, were randomly assigned to receive risperidone or clozapine for 8 weeks after a 7-day washout period. After a 1-week dose-titration phase, doses were fixed at 6 mg/day of risperidone and 300 mg/day of clozapine for 1 week and then adjusted according to each patient's response. The final mean doses were 6.4 mg/day of risperidone and 291.2 mg/day of clozapine. Treatment efficacy and safety were evaluated with several well-known rating scales.
                Both risperidone and clozapine significantly reduced the severity of psychotic symptoms (scores on the Positive and Negative Syndrome Scale and the Clinical Global Impression scale) from baseline, with no significant between-group differences. At endpoint, 67% of the risperidone group and 65% of the clozapine group were clinically improved (reduction of 20% or more in total Positive and Negative Syndrome Scale score). Risperidone appeared to have a faster onset of action. In both groups extrapyramidal symptoms and other adverse events were few, and their severity was generally mild. Neither group showed evidence of a relation between drug plasma concentrations and clinical effectiveness.
                Risperidone was well tolerated and as effective as medium doses of clozapine in patients with chronic schizophrenia who had been resistant to or intolerant of conventional neuroleptics. Remoxipride and clozapine are new neuroleptics that are thought to be superior to the substances in use by their efficacy and tolerance. At the University Clinic of Psychiatry in Düsseldorf a double-blind study with 54 patients diagnosed as schizophrenic in accordance with DSM-III was conducted to record the influence of the neuroleptics remoxipride, clozapine and haloperidol on schizophrenic psychosis. The schizophrenic symptoms were rated by the AMDP-system (Arbeitsgemeinschaft für Methodik und Dokumentation in der Psychiatrie), Brief Psychiatric Rating Scale and the Clinical Global Impression on days 0, 7, 14, 21 and 28 of treatment to evaluate the degree of change in psychopathology. The tolerance of the neuroleptic treatment was checked by the doctor's overall impression and the somatic findings of the AMDP-system. All 3 neuroleptics reduced the schizophrenic symptoms to a similar degree but showed differentiation as to their side effects. 1. The atypical antipsychotic risperidone may constitute an alternative to clozapine, the current treatment of choice for refractory schizophrenia. The objectives of this study were to evaluate the effectiveness of risperidone in comparison to clozapine in everyday practice and to assess the feasibility of a pragmatic trial procedure. 2. Patients were randomly assigned to open-label clozapine or risperidone treatment for 10 weeks and treatment outcomes were assessed blindly. Twenty-one patients were recruited and nineteen entered the randomized phase. 3. Five of 10 participants allocated to clozapine and one of nine risperidone participants dropped out before study completion. Five clozapine patients and six risperidone patients achieved clinical improvement, defined as a 20% decrease in the Positive and Negative Symptom Scale (PANSS) total score. No significant differences between the groups were detected in baseline or endpoint positive or negative symptoms, disease severity, or global or social functioning scores. Patients' opinion on the drugs did not differ between groups. 4. The findings of the intention-to-treat analysis of this study corroborates previous findings that risperidone may be equally effective as clozapine, and supports the feasibility and need of a multicenter randomized pragmatic trial with sufficient power to detect differences between treatments.
The equal effectiveness and tolerability of new atypical drugs in comparison with clozapine is not yet demonstrated. Lack of statistical power to determine the comparative efficacy and effectiveness of newer atypical drugs makes it difficult to judge whether newer drugs are more effective, less effective or equivalent. Trials of sufficient power, with longer duration, measuring clinically important outcomes, are needed to assess the true comparative clinical effectiveness, tolerability and cost effectiveness of newer drugs in relation to clozapine.