Population pharmacokinetics as a method to detect variable risperidone exposure in patients suffering from dementia...

This study was intended to compare the consistency of risperidone exposure in patients who have dementia and behavioral disturbances treated in a psychiatric hospital versus a community care setting.

Population pharmacokinetic modeling was used to assess the consistency of risperidone exposure in Alzheimer's disease patients with agitation. The ratio of predicted to observed drug concentrations (Cpred/Cobs) derived from this model was used to compare exposure in the inpatient versus long-term/home care settings using both the mean and the variance of this term across groups.

The modeled Cpred/Cobs ratios had a much higher within-subject variance in the inpatients than in the community care patients (117.03% vs 72.35%; P < 0.001). The central tendencies of the Cpred/Cobs ratios across the 2 groups were not significantly different.

Exposure to risperidone was more variable in a psychiatric hospital than in a community care setting. Future research may help to identify the specific contributors to the increased variance observed in this pilot study.