Is mirtazapine compatible with breast-feeding?
Mirtazapine is an antidepressant with a bioavailability of 50% and a half-life of 20-40 hours (1).
This question has previously been answered in Drugline. At that time, there was only one published case. A maximum infant dose of 1% of the maternal weight-adjusted dose was calculated, and no adverse effects in the child were noted. The manufacturer had knowledge of two additional cases. In one of these, a nine-month-old child experienced adverse effects (nausea, diarrhoea and vomiting) six days after the mother initiated of mirtazapine (15 mg/day) (2).
In a recently published study the transfer of mirtazapine and its active metabolite, desmethylmirtazapine, in eight mother-infant pairs was investigated. The mothers had been treated with mirtazapine a median of 32 days (range 6-129 days), and were taking single daily doses of mirtazapine of a median of 38 mg (range 30-120 mg). The mean milk/plasma ratio was 1.1 for mirtazapine and 0.6 for the metabolite. The total relative infant dose for mirtazapine and desmethylmirtazapine was calculated to be in average 1.9% (range 0.7-3.1%) of the maternal weight-adjusted dose. In four of the infants, blood samples were drawn. Mirtazapine was only detected in plasma from one of the children (1.5 ug/l) and the metabolite in none. None of the infants showed any adverse effects (3).
Mirtazapine is excreted into breast milk. The reported total relative infant dose has varied between 0.7-3.1% of the maternal weight-adjusted dose and no adverse effects have been observed in the published cases. Based on existing data, mirtazapine seems to be compatible with breast-feeding. However, the infant should be observed for undesirable effects.
Senast ändrad 2018-09-20