Risperidone and olanzapine: optimal dosing for efficacy and tolerability in patients with schizophrenia

Schizophrenia is a chronic and debilitating disorder whose effective pharmacological management is often less than optimal. For several decades, pharmaceutical treatment for this disorder consisted of conventional neuroleptics such as haloperidol and chlorpromazine. However, the limitations of these drugs have driven the development of newer antipsychotics that are designed to be more efficacious and more tolerable than conventional agents. Newer agents available for consideration as first-line treatment options now include risperidone, olanzapine, sertindole and, more recently, quetiapine. Proper dosing has emerged as a vital factor in the effective use of these newer drugs. This report examines data derived from clinical trials and market research with risperidone and olanzapine to help clinicians determine the appropriate dose for efficacy and to appraise the adverse events associated with that efficacious dose. Current information suggests that, for most patients with schizophrenia, the optimal dose with respect to efficacy and tolerability of risperidone is < or = 6 mg/day. The optimal dose of olanzapine is less clear and may be 15 mg/day or higher. With the advent of these newer antipsychotics, clinicians now have more treatment options for the management of patients with psychotic disorders. Knowledge gained through clinical experience is needed to augment clinical trial results and to help define the most effective use of each of these agents.