Effects of sex and age on serum concentrations of antidepressants under naturalistic conditions

Summary Introduction: TDM data of psychotropic medication are often obtained from samples of highly selected individuals, in contrast to a typical sample of psychiatric patients. Therefore studies under naturalistic conditions are important to clarify the full clinical relevance of TDM. Methods: We retrospectively evaluated TDM-analyses of antidepressants from 2008 to 2010 in an unselected sample of patients in a standard clinical setting. We examined the influence of sex and age on dose-corrected serum concentrations. Results: Considering only one determination per patient 790 TDM-analyses of amitriptyline (AMI+NOR), 182 of citalopram (CIT), 160 of clomipramine (CLO+N-CLO), 320 of doxepine (DOX+N-DOX), 408 of escitalopram (ESC), 213 of fluoxetine (FLU+N-FLU), 95 of maprotiline (MAP), 945 of mirtazapine (MIR), 88 of sertraline (SER) and 794 of venlafaxine (VEN+ODV) were left. Women had significantly higher dose-corrected serum levels of AMI+NOR, CIT, DOX+N-DOX, MIR and VEN+ODV and patients older than 60 years had significantly higher dose-corrected serum levels of AMI+NOR, CIT, DOX+N-DOX, MIR, SER and VEN+ODV. Females > 60 years had a remarkably higher dose-corrected serum concentration of AMI+NOR, CIT, DOX+N-DOX, MIR and VEN+ODV in contrast to males ≤ 60 years. Discussion: Our results suggest that TDM is recommendable in naturalistic settings, as variables like sex and age have a significant influence on the serum levels of different antidepressant drugs.