Safety and Efficacy of Long-Acting Risperidone in Schizophrenia: A 12-Week, Multicenter, Open-Label Study in Stable Patients Switched From Typical and Atypical Oral Antipsychotics

Background: The safety and efficacy of the first long-acting injectable atypical antipsychotic, risperidone, were assessed in stable patients with schizophrenia switched from oral antipsychotic medications.

Method: Data were collected between July 1, 2001, and October 25, 2002. The study population included patients from clinics, hospitals, and physicians' offices. After a 4-week run-in period, symptomatically stable patients with schizophrenia (DSM-IV) who had been taking haloperidol (N = 46), quetiapine (N = 45), or olanzapine (N = 50) received 25 mg of long-acting risperidone. The oral antipsychotics were continued for 3 weeks after the first injection of long-acting risperidone. Injections were administered every 2 weeks at 25 mg up to a maximum dose of 50 mg for 12 weeks in this multicenter, open-label study.

Results: Long-acting risperidone was well tolerated. Of the 141 patients who participated in the study, the most frequently reported adverse events were insomnia (16%), headache (15%), psychosis (11%), and agitation (11%). The mean increase in body weight was 0.4 kg. No other clinically relevant laboratory abnormalities or significant electrocardiogram changes were observed during the 12-week treatment. Extrapyramidal Symptom Rating Scale total scores were reduced during treatment with long-acting risperidone. Improvements in symptoms of schizophrenia were observed with long-acting risperidone at week 4 and continued through the 12-week treatment with significant reductions in total Positive and Negative Syndrome Scale (PANSS) scores at week 8 (-2.5, p < .01) and week 12 (-3.9, p < .001). At endpoint, 37% (50/135) of these stable patients were rated as clinically improved (>= 20% decrease in PANSS total scores).

Conclusions: Switching treatment from oral antipsychotics to long-acting risperidone without an intervening period of oral risperidone was safe and well tolerated. Long-acting risperidone also significantly reduced the severity of symptoms in these stable patients with schizophrenia.

J Clin Psychiatry 2004;65(8):1084-1089