Clinical outcome and olanzapine plasma levels in acute schizophrenia

Purpose: This open label study was performed to evaluate the reletionship between the plasma concentration of olanzapine and the response in acute schizophrenic inpatients. Material and methods. A total of 54 inpatients, 38 males and 16 females, age ranging from 18 to 75 years, affected by schizophrenia during an exacerbation phase were included in the study. Olanzapine (OLZ) was started at a dose of 5-20 mg/day and was increased to a mean dose of 15.27 mg +/- 5.53 sd. Patients were evaluated at baseline, and after 2 weeks, by using BPRS, PANNS, HRS-D, EPSE and ACS. Results.BPRS and total PANSS showed a statistically significant improvement at the end of the study. Olanzapine plasma levels (PL)ranged from 5 to 120 ng/ml (mean 33.15 ng/ml; sd 28.28) and showed a positive correlation with OLZ dosage. A significant curvilinear correlation between OLZ PL and clinical improvement (BPRS, PANSS and HRS-D percent of amelioration) was observed. Conclusion. Olanzapine plasma level determination seems to be a useful tool in optimizing acute treatment particularly for more problematic cases.