Risperidone efficacy

Umbricht D, Kane JM. Risperidone efficacy and safety. Schizophr Bui 1995 21 593-606.r... 

Kane JM, Eerdekens M, Lindenmayer JP, et al. Long-acting injectable risperidone Efficacy and safety of the first long-acting atypical antipsychotic. Am J Psychiatry 2003 160 1125-1132. 

Chan, H. Y. etal. (2007). Efficacy and safety of aripiprazole in the acute treatment of schizophrenia in Chinese patients with risperidone as an active control a randomized trial. /. Clin. Psychiatry, 68, 29-36. 

Of the atypical antipsychotics, clozapine, olanzapine, and risperidone have been studied the most. Clozapine was used to treat 10 treatment refractory acutely manic patients and 15 schizomanic patients. Using reduction in the YMRS score as the outcome measure, 72% improved (non-rapid cycling, bipolar patients). Comparison of olanzapine (5-20 mg) with placebo showed significant reduction of the YMRS in 49% vs. 24% of subjects by 3 weeks, with significant change evident by the first week. In a trial comparing risperidone at 6 mg with haloperidol at 10 mg and low-dose lithium (800-1200 mg/day) efficacy was similar over the 28 days of the trial. 

The main indications for atypical antipsychotics are the acute and maintenance treatment of schizophrenic disorders, with an emphasis on the treatment of refractory and chronic disorders. However, because of the lower risk of EPS and in particular of tardive dyskinesia, there is a tendency toward a wider range of indications for some of the atypical neuroleptics. Favorable effects in drug-induced psychoses have been demonstrated for olanzapine. Clozapine seems effective in the treatment and relapse prevention of manic episodes and bipolar disorders, and risperidone has been shown to have good efficacy in conduct disorders and in the pervasive developmental disorders. 

Several case reports suggest good efficacy of risperidone in child and adolescent schizophrenia (for review see Toren et al., 1998). 

Findling, R., Aman, M., and Derivan, A. (2000). Long-term safety and efficacy of risperidone in children with significant conduct problems and borderline IQ or mental retardation. Presented at the 39th Annual American College of Neuropsychopharmacology, San Juan, Puerto Rico, December 2000. 

Atypical neuroleptics have a better side-effect profile, and several studies have confirmed their efficacy. Risperidone has been found effective in the treatment of dementia in patients with agitation (N. Hermann et al. 1998 Jeanblanc and Davis 1995 Jeste et al. 1996 I. R. Katz et al. 1999 Lavretsky and Sultzer 1998), in patients with Lewy body disease (Geizer and Ancill 1998), or in patients with L-dopa-induced hallucinations (Meco et al. 1994). Risperidone has better tolerability than classic neuroleptics such as thioridazine and haloperidol (Frenchman and Prince 1997). No studies of the efficacy of olanzapine in the treatment of agitation in patients with dementia have been done, but its use is widely advocated. 

In a double-blind, multicenter, prospective study, Csernansky et al. (2002) showed that among patients with clinically stable chronic schizophrenia or schizoaffective disorder the risk of relapse was significantly lower with risperidone than with haloperidol (34% vs. 60%, P < 0.001). The means of daily doses of risperidone ( 4.9mg) and haloperidol (11.7mg) were similar to those used in clinical practice (Csernansky et al.y 2002). The reduced risk of relapse found with risperidone could be due to its superior efficacy, better tolerability or both (Csernansky et al.y 2002). 

Therapeutic Efficacy. The therapeutic efficacy of risperidone for schizophrenia has been well established in several controlled trials conducted worldwide ( 74, 75). The clinical efficacy trials performed to support approval of risperidone by regulatory agencies have all been published. Therefore, it is appropriate to combine these data using meta-analytic techniques to explore the efficacy of risperidone compared with neuroleptics. For most drugs, the relationship of dose and response is defined by the classic sigmoidal curve. Thus, as the dose (or plasma level) increases beyond a threshold and reaches the linear portion of the curve, response increases. Once the dose is high enough to produce maximal clinical response, the dose-response curve then levels off. 

Janicak et al. (87) studied the relative efficacy and safety of risperidone versus haloperidol in the treatment of schizoaffective disorder. Sixty-two patients (29 depressed type, 33 bipolar type) entered a randomized, double-blind, 6-week trial of risperidone (up to 10 mg/day) or haloperidol (up to 20 mg/day). They found no difference between risperidone and haloperidol in the amelioration of psychotic and manic symptoms nor any significant worsening of mania with either agent. For the total PANSS, risperidone produced a mean decrease of 16 points from baseline, compared with a 14-point decrease with haloperidol. For the total CARS-M scale, risperidone and haloperidol produced mean change scores of 5 and 8 points, respectively and for the CARS-M mania factor, 3 and 7 points, respectively. 

Olanzapine Versus Risperidone. Several naturalistic studies compared olanzapine with risperidone, usually finding these drugs produced the same overall efficacy. One study conducted at Riverview Hospital in British Columbia, however, found that 60% of risperidone patients were responders, compared with only 27% of olanzapine patients, and that the speed of response to risperidone was 14 days compared with 23 days with olanzapine. The mean dose of risperidone was 4.8 mg/day and for olanzapine 14.3 mg/day (120). 

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