Long-term therapeutic drug monitoring of risperidone and olanzapine identifies altered steady-state pharmacokinetics: a clinical, two-group, naturalistic study.

Background And Objective: Conflicting therapeutic drug monitoring (TDM) results have been reported for risperidone and olanzapine. This study set out to examine the long-term pharmacokinetics of risperidone and olanzapine in a locked skilled nursing facility where medication administration was controlled by nursing staff.

Methods: TDM was performed in a long-term treatment protocol for risperidone and olanzapine in 67 refractory chronic schizophrenic patients in a locked, skilled nursing facility.