Costs and effectiveness of therapeutic drug monitoring in psychiatry

Though therapeutic drug monitoring (TDM) is increasingly used to improve psychopharmacotherapy, its cost-effectiveness is a matter of debate. Bioanalytical costs reportedly amount to 20 to 30 € per sample. Automated procedures such as high performance liquid chromatography with column switching may be less expensive. When analyzing 40 samples per day total costs are about 7 € per sample, but they increase to 37 € when only 5 samples are analyzed per day. For nortriptyline, it has been shown that pharmacokinetic dosing has an economic impact, for tricyclic antidepressants, TDM is cost-effective by reducing the risk of intoxications, and for selective serotonin reuptake inhibitors, TDM may decrease drug costs. Evidence is thus growing that TDM of psychoactive drugs is cost-effective. This needs to be shown by more studies. Thereby it must also be considered that an adequate use of TDM in daily clinical practice is far from optimal.