Optimal dose of risperidone and olanzapine for patients with schizophrenia in Taiwan.

Risperidone and olanzapine-administration data were collected for schizophrenia patients treated at four Taiwanese medical centres. Only stable patients maintained on a medication at a dose that had remained unchanged for more than 1 month were included in the analysis. Of the 268 cases, 175 were treated with risperidone and 93 with olanzapine at mean daily doses of 3.56 +/- 1.54 mg and 12.21 +/- 4.99 mg, respectively. The majority of the risperidone-treated patients (73.2%) received 2-4 mg per day, with another 19.0% receiving 5-6 mg. A daily dose of 10-20 mg was received by 82.9% of the olanzapine group. Although the mean daily doses for both drugs were slightly higher for inpatients than outpatients, statistical significance was not achieved. Further, no gender or age-group dose differences were demonstrated for either drug.