Treatment of Schizophrenia With Long-Acting Injectable Risperidone: A 12-Month Open-Label Trial of the First Long-Acting Second-Generation Antipsychotic

Background: The long-term safety and efficacy of long-acting injectable risperidone, the first long-acting second-generation antipsychotic, were evaluated in stable patients with schizophrenia.

Method: After a 2-week run-in period during which patients with DSM-IV schizophrenia received flexible doses of 1 to 6 mg of oral risperidone, patients received injections of 25 mg, 50 mg, or 75 mg of long-acting risperidone every 2 weeks for 12 months. Severity of extrapyramidal symptoms was assessed with the Extrapyramidal Symptom Rating Scale (ESRS), and efficacy was assessed with the Positive and Negative Syndrome Scale (PANSS). This study was conducted from March 29, 1999 to July 19, 2000.

Results: The subjects were 615 patients with schizophrenia who received at least 1 injection of long-acting risperidone. The 12-month trial was completed by 65% of patients. Treatment was discontinued because of adverse events in 5% of patients. Extrapyramidal symptoms as adverse events were reported by 25% of the patients. Severity of extrapyramidal symptoms (according to ESRS scores) was low at baseline and decreased in each of the groups during the 12 months. The other most common adverse events were anxiety in 24%, insomnia in 21%, psychosis in 17%, and depression in 14% of the patients. Little pain was associated with the injections. Severity of symptoms of schizophrenia was improved in each group, with significant reductions in PANSS total scores (p < .01) and positive (p < .01) and negative (p < .001) factor scores.

Conclusion: In terms of both safety and efficacy, symptomatically stable patients with schizophrenia benefit from being switched to long-acting injectable risperidone.