Potential cost-effectiveness of therapeutic drug monitoring for depressed patients treated with citalopram.

BACKGROUND For patients treated with citalopram, it was recently shown that serum concentrations above 50 ng/mL on day 7 of treatment are associated with an improved therapeutic outcome. The aim of this post hoc analysis was to calculate a potential cost-effectiveness of therapeutic drug monitoring (TDM) considering costs for hospitalization, medication, and drug analysis. METHODS The study included patients with major depression. Weekly measurements of serum concentrations and assessments of psychopathology were conducted. RESULTS Fifty-five patients were included in this analysis. For patients with high citalopram serum concentrations (>50 ng/mL), the mean duration of hospitalization was 49 ± 20 days, and it was 72 ± 37 days (P = 0.03) in the group with low drug concentrations (<50 ng/mL). Considering daily costs for hospitalization of 250€,;, the potential savings amounted to 5750€,; per patient for the 23 days. Assuming that 11% of the variation of duration of hospitalization per patient were attributed to the serum concentration of the drug, the resulting savings were 633€,; per patient. Considering the officially listed price of 21€,; per TDM assay, total costs for weekly measurements over a period of 10 weeks of hospitalization were 210€,;. In the groups with high and low serum concentrations, daily costs for citalopram medication were 3.00 ± 0.80€,; and 2.42 ± 0.70€,;, respectively (P = 0.002), and the mean number of comedications was nearly identical, that is, 1.87 ± 1.74 and 1.81 ± 1.86 drugs, respectively (P = 0.919). CONCLUSIONS The data taken together indicate that TDM-guided dosing of citalopram has the potential to be cost effective by reducing the length of hospitalization.