• sertraline;
  • N-desmethylsertraline;
  • human milk;
  • infant dose

Aims To characterise milk/plasma (M/P) ratio and infant exposure, for sertraline and N-desmethylsertraline, in breast-feeding women taking sertraline for the treatment of depression.

Methods Eight women (mean age 28 years) taking sertraline (1.05 mg kg−1 day−1 ) and their infants (mean age 5.7 months) were studied. Sertraline and N-desmethylsertraline in plasma and milk were measured by high-performance liquid chromatography over a 24 h dose interval at steady-state. M/P values were estimated from area under the plasma and milk concentration-time curves. All milk produced was collected over the dose interval. Infant exposure was estimated as the product of actual or estimated milk production, and average drug concentration in milk, normalized to body weight and expressed as a percentage of the weight-adjusted maternal dose.

Results Mean milk production was 321 ml day−1 (range 34–974 ml). Mean M/P values of 1.93 and 1.64 were calculated for sertraline and N-desmethylsertraline respectively. Infant exposure estimated from actual milk produced was 0.2% and 0.3% of the weight-adjusted maternal dose for sertraline and N-desmethylsertraline (as sertraline equivalents) respectively. When calculated from estimated milk production (0.15 l kg−1 day−1 ), infant exposure was significantly greater (P<0.0001) at 0.90% and 1.32% for sertraline and N-desmethylsertraline respectively. Neither sertraline nor its N-desmethyl metabolite could be detected in plasma samples from the four infants tested. No adverse effects were observed in any of the eight infants and all had achieved normal developmental milestones.

Conclusions Irrespective of the method of calculation of infant exposure, the mean total dose of sertraline and its N-desmethyl metabolite transmitted to infants via breast-feeding is low and unlikely to cause any significant adverse effects.