Compliance with SSRI medication during 6 months of treatment for major depression: an evaluation by determination of repeated serum drug concentrations.
BACKGROUND
A recent estimation in a psychiatric cohort showed numbers of noncompliance between 10% and 60%. Therapeutic drug monitoring (TDM) is one method assessing compliance by analysis of drug concentration in the blood.


METHODS
During a 24-week phase IV clinical trial, five repeated serum samples of sertraline (SERT) and N-desmethylsertraline (DSERT), trough values in steady state, were collected per patient. Previous results show that the intraindividual variation over time of the ratio DSERT/SERT is low. Hence, we hypothesized that significant partial noncompliance could be scrutinized further by an assessment of the DSERT/SERT ratio. The main aim was to test the applicability of a novel type of TDM procedure based on repeated metabolite/parent compound ratio measurements.


RESULTS
9.4% of the per-protocol population in the trial (n = 96) were in either hidden total (n = 4) or hidden partial (n = 5) noncompliance. Only by using the novel TDM ratio screening method could a majority of these patients be identified.
Reis
Margareta
M
Division of Clinical Pharmacology, Linköping University, Linköping, Sweden. margareta.reis@klinfarm.lu.se
Aberg-Wistedt
Anna
A
Agren
Hans
H
Akerblad
Ann-Charlotte
AC
Bengtsson
Finn
F
D000293:Adolescent; D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D010349:Patient Compliance; D010507:Periodicity; D017367:Selective Serotonin Reuptake Inhibitors / Q000097:blood* / Q000627:therapeutic use*; D020280:Sertraline / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D013997:Time Factors
D017367:Selective Serotonin Reuptake Inhibitors; D020280:Sertraline; C065162:desmethylsertraline