Antidepressant drugs in children and adolescents: analytical and demographic data in a naturalistic, clinical study.

Pharmacokinetics of antidepressant drugs (ATDs), in terms of steady-state and trough values, in patients from Child and Adolescent Psychiatry centers in the midsouth-eastern part of Sweden, were evaluated, and the use of ATDs in this population were described. Patients to be prescribed an ATD were studied between 2002 and 2004. Two hundred eleven children, 64% girls and 36% boys (ages 8-20 years) were evaluated. The primary indication for the antidepressant treatment was depression in 69% of subjects. The median body mass index was 20.2 kg/m² (range, 12.4-38.6 kg/m²). Suspected adverse drug reactions were spontaneously reported in 31% (no serious). Monotherapy was indicated in 49% of request forms. The most common drug combination with the ATD was oral contraceptives. The concentrations of drugs in the patient evaluated population to referenced data for adults from the dose administered were as expected in 63%, higher than expected in 26% and lower than expected in 11%. The most prescribed ATD was sertraline (SERT). Dose-concentration relationships for SERT and metabolite desmethylsertraline (DSERT) were seen, rs = 0.48 and rs = 0.5, respectively. No relationship was found between dose and ratio DSERT/SERT. The median daily dose was 50 mg (range, 12.5-150 mg), SERT concentration 16 ng/mL (range, 3-88 ng/mL), and DSERT 33 ng/mL (range, 0-253 ng/mL). CYP2D6*4 was the most common poor metabolizer allele. Therapeutic drug monitoring may provide support to prescribing physicians to individual dose optimizing and to assess drug compliance, above all when ATDs are not well studied in pediatric patients before approval for general prescription.