Abstract
Introduction
This study assesses the utilization of antipsychotic therapeutic drug monitoring (TDM) and describes characteristics of appropriate and inappropriate TDM at a state psychiatric hospital.
Methods
A retrospective, descriptive review was conducted for antipsychotic TDM completed between December 1, 2009, and June 30, 2011, at a 65-bed adult inpatient extended-care and forensic state psychiatric hospital.
Results
One hundred thirty-three (n = 133) antipsychotic serum levels were collected from 44 patients during the study period. Sixty-nine percent (69%) of the TDM were deemed inappropriate, 28% were appropriate, and 3% could not be designated appropriate or inappropriate owing to the lack of information regarding steady-state conditions. The primary reason for inappropriate TDM was lack of documentation with regard to the indication for TDM (n = 79, 59.3%), the intervention following laboratory analysis (n = 88, 66%), or both. Appropriate TDM was associated with a lower laboratory cost for antipsychotic serum level ($48.98 ± $53.49 versus $72.06 ± $51.02, P < .05), lower daily cost of scheduled psychiatric medications ($17.72 ± $23.03 versus $32.26 ± $31.05, P < .05), lower daily cost of total medications ($19.28 ± $24.91 versus $33.82 ± $31.03, P < .05), fewer scheduled psychiatric medications (2.95 ± 1.90 versus 4.04 ± 2.19, P < .01), and fewer total scheduled medications (5.95 ± 3.60 versus 7.60 ± 3.29, P < .05). Inappropriate TDM led to approximately $6,753 in avoidable laboratory costs over a 20-month period.
Discussion
Therapeutic drug monitoring is a complex process with many points at which errors may occur. The majority of antipsychotic levels at this state psychiatric hospital were not documented in a way that was clinically useful. Inappropriate TDM was associated with increased laboratory and medication costs.
Using pharmacogenomics and therapeutic drug monitoring to guide drug selection and dosing in outpatient mental health comprehensive medication management
