Transfer of the antidepressant mirtazapine into breast milk

Pharmacy Department, Women's and Children's Health Service, Subiaco, Australia.
British Journal of Clinical Pharmacology (Impact Factor: 3.88). 04/2007; 63(3):322-7. DOI: 10.1111/j.1365-2125.2006.02773.x
Source: PubMed


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

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Available from: Rolland Kohan, Oct 11, 2014
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    • "The pharmacokinetics of mirtazapine during lactation have recently been investigated by Kristensen et al. (2006).[66] Both mirtazapine and its metabolite were detected in breast milk; however, the dose received by the infant relative to an adult dose was only 1.5%, and a detectable serum mirtazapine was found in only one of the infants. "
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