Comparison of cost, dosage and clinical preference for risperidone and olanzapine.

Background: Because risperidone and olanzapine have similar efficacy and tolerability in the treatment of schizophrenia, costs, physician experience, and preference become relevant considerations in making treatment decisions. The purpose of this paper is to compare daily treatment costs of risperidone and olanzapine, and to examine psychiatrists' clinical preferences.
Method: Dosage information was obtained from a national Ministry of Health registry and a national survey of psychiatrists. In addition, psychiatrists' clinical preference of antipsychotic medication and dosage for patient subtypes were examined by the national survey.
Results: Data from the registry and national survey estimated the mean daily dose of risperidone to be one-third that of olanzapine, irrespective of patient subtype. Taking into account drug costs and dosage requirements, the average daily retail price was US $6.85 for risperidone and US $13.60 for olanzapine. Psychiatrists preferred risperidone for first-episode psychosis and elderly psychosis, and olanzapine for patients sensitive to EPS. They rated the drugs equally effective on positive and negative symptoms, for chronic patients, for treatment-refractory patients and relapse prevention.
Conclusions: Risperidone has a substantial cost advantage over olanzapine, and was preferred by psychiatrists for more indications.