Article date: March 2007
By: J. H. Kristensen, Kenneth F. Ilett, Jonathan Rampono, Rolland Kohan, L. Peter Hackett, in Volume 63, Issue 3, pages 322-327
What is already known about this subject
• There is presently only a single case report on mirtazapine transfer into breast milk and its effects in the breast‐fed infant.
What this study adds
• Most importantly, we have provided quantitative data on the absolute and relative infant doses of mirtazapine and its active metabolite.
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 µg 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.
DOI: 10.1111/j.1365-2125.2006.02773.x
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