Transfer of the antidepressant mirtazapine into breast milk

Br J Clin Pharmacol. 2007 Mar;63(3):322-7. doi: 10.1111/j.1365-2125.2006.02773.x. Epub 2006 Sep 13.

Abstract

Aims: To investigate the transfer of mirtazapine and desmethylmirtazapine into milk and to calculate dose to the infant via milk.

Methods: Plasma and milk samples were obtained from eight breast-feeding women who were taking a median dose of 38 mg mirtazapine per day. Milk/plasma ratio (M/P) and infant doses were estimated by standard methods. The infants were examined clinically and in four infants blood was taken for analysis.

Results: Mean (95% confidence interval) relative infant doses for mirtazapine and desmethylmirtazapine (n = 8) were 1.5% (0.8, 2.2) and 0.4% (0.2, 0.6) respectively. The mean M/P (area under curve n = 4, single or paired samples n = 3) was 1.1 (0.7,1.5) for mirtazapine and 0.6 (0.5, 0.7) for desmethylmirtazapine. No adverse effects were seen. Mirtazapine was detected (1.5 microg l(-1)) in only one of four infants tested.

Conclusion: We suggest that mirtazapine use by lactating women is safe for the breast-fed infant. Nevertheless, each decision to breast feed should always be made on the basis of an individual risk/benefit analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antidepressive Agents, Second-Generation / adverse effects*
  • Antidepressive Agents, Tricyclic / adverse effects*
  • Breast Feeding*
  • Depression, Postpartum / drug therapy*
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Mianserin / adverse effects
  • Mianserin / analogs & derivatives*
  • Milk, Human / chemistry
  • Mirtazapine
  • Pregnancy

Substances

  • Antidepressive Agents, Second-Generation
  • Antidepressive Agents, Tricyclic
  • desmethylmirtazapine
  • Mianserin
  • Mirtazapine