Long-Acting Risperidone Well Tolerated, Effective in Schizophrenia

Laurie Barclay, MD

June 06, 2003

June 6, 2003 — Long-acting injectable risperidone was well tolerated and effective in schizophrenia, according to the results of a multicenter, randomized trial published in the June issue of the American Journal of Psychiatry. This offers a new mode of treatment that may improve long-term outcome.

"Poor compliance is common even with the atypical agents, and additional treatment options for patients with schizophrenia and other psychoses are needed," write John M. Kane, MD, from the Zucker Hillside Hospital in Glen Oaks, New York, and colleagues. "Specifically, many clinicians have expressed the need for a long-acting atypical antipsychotic."

Long-acting injectable risperidone is the first such agent to become available, according to the authors. Fluctuations in plasma drug levels and peak plasma drug levels are lower with long-acting risperidone than after oral dosing, suggesting more consistent and predictable plasma drug levels with superior tolerability.

In this 12-week, double-blind study, patients received placebo or long-acting risperidone, 25 mg, 50 mg, or 75 mg, via biweekly intramuscular injection. Of 554 patients enrolled, 400 entered the double-blind study, and 370 received at least one postbaseline assessment.

All three risperidone groups fared significantly better than the placebo group in the primary measure of efficacy, which was the change in total score on the Positive and Negative Syndrome Scale. At endpoint, mean changes in score were -6.2 for 25 mg risperidone, -8.5 for 50 mg, -7.4 for 75 mg, and +2.6 for placebo. Improvements in positive and negative symptoms were also significantly greater in the risperidone groups.

Overall, long-acting risperidone was well tolerated, with extrapyramidal symptoms spontaneously reported by 13% in the placebo group, 10% in the 25-mg risperidone group, 24% in the 50-mg group, and 29% in the 75-mg risperidone group. Severity of extrapyramidal symptoms was mild at baseline and throughout the trial in all groups. Mean weight changes were relatively small in the risperidone groups, and the patients rated the injection site pain as low.

"Long-acting injectable risperidone was efficacious and well tolerated and provides both clinicians and patients with a new mode of treatment that can improve the outcome of long-term therapy," the authors write. "The study results indicate that 25 mg of long-acting injectable risperidone given every 2 weeks appears to offer the optimum risk/benefit profile for most patients requiring maintenance treatment with an antipsychotic."

Johnson & Johnson supported this study and employs some of its authors.

Am J Psychiatry. 2003;160:1125-1132

Reviewed by Gary D. Vogin, MD


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