Comparative efficacy and safety of long-acting risperidone and risperidone oral tablets.

A double-blind study of long-acting injectable risperidone and oral risperidone tablets was conducted in 640 patients with schizophrenia. All patients received flexible doses of 1-6 mg of oral risperidone for 8 weeks. Doses were stable during weeks 5-8. At the end of week 8, symptomatically stable patients were randomly assigned to receive long-acting risperidone (active injections, dummy oral) or continued oral risperidone (dummy injections, active oral) for 12 weeks. Significant improvements were demonstrated from baseline to endpoint in Positive and Negative Syndrome Scale (PANSS) total (P<0.001) and factor scores (P<0.05) in both groups. According to a noninferiority analysis, the two treatments showed comparable efficacy in total PANSS scores over the short-term. No unexpected adverse events were recorded. The findings indicate that symptomatically stable patients can be safely switched from oral risperidone to long-acting injectable risperidone without compromising efficacy.