Transfer of the antidepressant mirtazapine into breast milk.
OBJECTIVE
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.


CONCLUSIONS
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.
Kristensen
J H
JH
Pharmacy Department, Women's and Children's Health Service, Subiaco, Australia.
Ilett
Kenneth F
KF
Rampono
Jonathan
J
Kohan
Rolland
R
Hackett
L Peter
LP
D018687:Antidepressive Agents, Second-Generation / Q000009:adverse effects*; D000929:Antidepressive Agents, Tricyclic / Q000009:adverse effects*; D001942:Breast Feeding; D019052:Depression, Postpartum / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008803:Mianserin / Q000009:adverse effects / Q000031:analogs & derivatives*; D008895:Milk, Human / Q000737:chemistry; D000078785:Mirtazapine; D011247:Pregnancy
D018687:Antidepressive Agents, Second-Generation; D000929:Antidepressive Agents, Tricyclic; C517416:desmethylmirtazapine; D008803:Mianserin; D000078785:Mirtazapine