Effect of Cytochrome P450 2D6 Genotype on Maternal Paroxetine Plasma Concentrations during Pregnancy

Background and Objective Increasing numbers of women in childbearing years are treated with antidepressants. Concerns regarding fetal exposure to medication has led to large studies on drug effects on birth outcome and on the risk of congenital anomalies. The risk of adverse effects due to paroxetine use during pregnancy has been associated with the extent of exposure. Nevertheless, few studies have covered dosing aspects in order to minimize fetal antidepressant exposure while limiting the risk of treatment failure. Essential pharmacokinetic data in pregnancy are lacking, even regarding paroxetine, one of the most commonly used antidepressants. We examined the changes of maternal paroxetine concentrations during pregnancy in relation to cytochrome P450 (CYP) 2D6 genotype.