Sertraline and norsertraline levels in three breastfed infants

In assessing the safety of medication use in breastfeeding, it is important to know whether the drug used by the mother will be present in the breastfed infant. Compared with data for tricyclic antidepressants (TCAs), which have generally not been found in the plasma of breastfed infants, there are few data on the use of serotonin selective reuptake inhibitors (SSRIs) in breastfeeding. This poses a dilemma for breastfeeding women and their treating clinicians, because of the enhanced tolerability of SSRIs compared with TCAs, and because some patients do not respond well to TCAs.

Sertraline and norsertraline plasma concentrations were measured in three breastfeeding mother-infant pairs. Maternal and infant plasma samples were drawn a few minutes apart. Two of the infants had an additional sample assayed without contemporaneous maternal samples examined. Drug assay was by high-performance liquid chromatography. Limit of reproducible quantifiability was 2 ng/mL, and limit of detectability was 1 ng/mL.

Maternal sertraline dose ranged from 50 to 100 mg/day. All infant plasma samples showed low levels (< 2 ng/mL) of either sertraline and norsertraline or norsertraline alone. Breastfeeding was continued, and the infants have shown no adverse effects on short-term follow-up.

These data suggest that sertraline and/or its almost inactive metabolite may be present at very low concentrations in the plasma of breastfed infants. No adverse effects were noted in the infants. Limitations of the findings and possible implications for the use of sertraline during breastfeeding are discussed.