[Gender- and age-related differences in dosage and serum concentration of psychotropic drugs].

BACKGROUND

The dose recommendations in the Norwegian Pharmaceutical Product Compendium (Felleskatalogen) are not gender-specific, despite evidence of gender-dependent differences in the metabolism of a number of drugs. The purpose of this study was to investigate the extent to which age and gender influence the prescription and serum concentration of psychotropic drugs.

MATERIAL AND METHOD

The prescribed doses and serum concentrations of antidepressant, antipsychotic and antiepileptic drugs were studied in relation to age and gender in 1533 patients.

RESULTS

Elderly women (≥ 65 years) were given somewhat lower doses of antidepressant drugs, but they had significantly higher serum concentrations than younger patients of either gender. Antidepressant drugs were prescribed in fairly high doses in the study population; the median number of defined daily doses was 1.5.

INTERPRETATION

The study suggests that when prescribing drugs, Norwegian physicians do not take sufficient account of the effect of age and gender on the pharmacokinetics of antidepressant drugs.