Risperidone: review and assessment of its role in the treatment of schizophrenia

OBJECTIVE: To review pharmacologic, pharmacokinetic, therapeutic, and safety information for the antipsychotic agent risperidone and to evaluate its place in the treatment of schizophrenia. DATA SOURCES: MEDLINE and Exerpta Medica databases; Janssen Pharmaceuticals; Food and Drug Administration Psychopharmacology Advisory Committee; PJB Publications; published articles and abstracts; unpublished research reports and abstracts. STUDY SELECTION: In vivo animal studies (pharmacology); volunteer studies (pharmacokinetics); clinical case reports, open clinical studies, and controlled clinical studies (clinical efficacy and adverse effects; long-term studies; studies in special populations. DATA EXTRACTION: Relevant data were extracted from published and unpublished source documents, evaluated, and summarized in tables for comparative review. Abstracts were used in 6 of 8 pharmacokinetic studies, 4 of 8 open clinical studies, and 2 of 9 controlled clinical studies. Use of abstracts limits the extent of data extracted. DATA SYNTHESIS: Risperidone is an effective treatment for positive symptoms of schizophrenia and may be effective for negative symptoms. Efficacy in treatment-resistant patients is inconclusive. In patients in whom low-to-moderate dosage is effective, there should be fewer and less severe adverse effects with risperidone than with haloperidol. Optimal dosage for schizophrenia appears to be 6 mg/d. Although data are limited, risperidone may be toxic on overdose. CONCLUSIONS: Risperidone is a useful addition to the antipsychotic drug armamentarium, but it should be viewed as an atypical antipsychotic agent. It is reasonable to consider a trial of risperidone in treatment-resistant schizophrenic patients prior to the use of clozapine and as a first-line treatment for newly diagnosed patients with schizophrenia.