Comparison of Risperidone and Olanzapine from the Point of View ofEfficacy, Tolerability and Treatment Costs

Overview

The RODOS study is an international multi-centre retrospective study, based on analysis of thepatient’s records in patients with schizophrenia, who were treated with risperidone or olanzapine. The objective of the project was to compare both medications from the point of view ofadministration, efficacy, tolerability, and costs of the treatment - all under the normal conditionsof clinical practice. In the Czech Republic, the RODOS study was conducted in three centres, andthere were 176 patients enrolled in total. In the risperidone group there were 93 patients, averageage 36.9 ± 13.8 years. In the olanzapine group there were 83 patients, average age 31.7 ± 11.7 years.There were two significant differences between the risperidone and olanzapine group: the age ofonset of the first symptoms (p = 0,0037) and the age on admission (p = 0,0054). The average dailydose of risperidone was 3.2 mg. The average daily dose of olanzapine was 13.9 mg. In the risperidone group 85% of respondents were reported, in the olanzapine group 86%. This difference wasnot significant. When the average time between the start of medication and the onset of itstherapeutic effect was compared, it was shown that the onset of the therapeutic effect of risperidone was faster than of olanzapine (7.9 versus 10 days, p = 0.006). There were no significantdifferences between the two groups in occurrence of adverse effects. Pharmaco-economical analysis of the daily treatment costs was performed using analysis of variance with covariates. Thismethod allowed for adjustment of the results to the baseline differences of both treatment groups.The adjusted price of the daily treatment dose of risperidone was 70.5 Czech Crowns (CZK). In thecase of olanzapine it was 245.7 CZK (p = 0.0001). If all the medication used was evaluated, theprice of daily treatment in the risperidone group was 81.5 CZK and in the olanzapine group it was256.5 CZK (p = 0.0001). The results of this study suggest that while the efficacy and tolerability ofboth medications were comparable, the cost of treatment was significantly higher in the olanzapine group.

Key words:
atypical neuroleptics, risperidone, olanzapine, efficacy, dosage, adverse effects, pharmacoeconomics.