Is Mirtazapine Safe in Breastfeeding

I am a breastfeeding mother and i want to know if it is safe to use Mirtazapine? Is Mirtazapine safe for nursing mother and child? Does Mirtazapine extracts into breast milk? Does Mirtazapine has any long term or short term side effects on infants? Can Mirtazapine influence milk supply or can Mirtazapine decrease milk supply in lactating mothers?

Excreted into breast milk in a clinically non-significant amount. Plasma level of breastfed infants from treated mothers with Mirtazapine are usually undetectable or very low. Not significant clinically based side-effects in the infants both at short and long-term have been observed. Isolated cases of galactorrhea have been reported. The poor extrauterine adaptation that may appear in neonates just after birth when the pregnant woman has been treated with selective reuptake-inhibitors of Serotonin like Venlafaxine or Mirtazapine, is seen to be mild if the baby is breastfed.

Limited information indicates that maternal doses of up to 120 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. If mirtazapine is required by the mother, it is not a reason to discontinue breastfeeding. Exclusively breastfed infants should be monitored for behavioral side effects and adequate growth if this drug is used during lactation.

A 14-week old infant was breastfed 6 times daily during maternal treatment with mirtazapine 30 mg daily. After 6 weeks of therapy, the infant was judged to have normal psychomotor development and no adverse effects, including sedation or abnormal weight gain.[1] Eight infants who averaged 6.3 months of age (range 1.5 to 13 months) were breastfed by mothers taking mirtazapine in an average dosage of 495 mcg/kg daily for 6 to 129 days. At the time they were studied, the average Denver developmental age in the 7 infants studied averaged 101% of normal. No adverse effects were noted in any of the infants.[2] A 6-week-old infant was exclusively breastfed by a mother who was taking mirtazapine 22.5 mg at daily at night beginning at 4 weeks postpartum. Weekly follow-ups of the infant found no sedation or alterations in weight gain, although the infant's weight was consistently below the 25th percentile even before mirtazapine was begun.[3] A 2-month-old infant was breastfed (extent not stated) by a mother taking 15 mg of mirtazapine daily during pregnancy and lactation. The mother stated that the infant had a higher birthweight and gained weight more rapidly than her previous 3 infants, and that unlike her other infants, this infant slept through the night at this age. The authors noted that these observations cannot necessarily be attributed to mirtazapine.[4] In a case series of 55 women who took mirtazapine during pregnancy and postpartum, 24 of their 56 infants were exclusively breastfed and 20 were partially breastfed. Of the infants who were exposed in utero during the third trimester, those who were breastfed either partially or exclusively had a lower frequency of poor neonatal adaptation syndrome than those who were exclusively formula fed. No sleeping or feeding problems were seen in any of the infants.[5]

Gynecomastia, hyperprolactinemia and galactorrhea were reported in an 89-year-old man after 21 months of therapy with mirtazapine 30 mg daily. Symptoms regressed 1 month after discontinuation and prolactin levels normalized.[6] A 28-year-old female inpatient developed galactorrhea, mastodynia, fatigue, and extended subcutaneous edema of the trunk and extremities 4 weeks after adjusting her mirtazapine dose to 30 mg daily. At this time her morning serum prolactin level was not elevated; however, 12 days later, morning serum prolactin was 32.1 mcg/L (normal range 4.79-23.3 mcg/L). Serum prolactin normalized, and edema and galactorrhea remitted within 1 week after discontinuing mirtazapine and starting escitalopram. Pituitary tumor was ruled out. Mirtazapine was probably the cause of the patient's symptoms.[7] The clinical relevance of these findings in nursing mothers is not known. The prolactin level in a mother with established lactation may not affect her ability to breastfeed. An observational study looked at outcomes of 2859 women who took an antidepressant during the 2 years prior to pregnancy. Compared to women who did not take an antidepressant during pregnancy, mothers who took an antidepressant during all 3 trimesters of pregnancy were 37% less likely to be breastfeeding upon hospital discharge. Mothers who took an antidepressant only during the third trimester were 75% less likely to be breastfeeding at discharge. Those who took an antidepressant only during the first and second trimesters did not have a reduced likelihood of breastfeeding at discharge.[8] The antidepressants used by the mothers were not specified. A retrospective cohort study of hospital electronic medical records from 2001 to 2008 compared women who had been dispensed an antidepressant during late gestation (n = 575; mirtazapine n = 12) to those who had a psychiatric illness but did not receive an antidepressant (n = 1552) and mothers who did not have a psychiatric diagnosis (n = 30,535). Women who received an antidepressant were 37% less likely to be breastfeeding at discharge than women without a psychiatric diagnosis, but no less likely to be breastfeeding than untreated mothers with a psychiatric diagnosis.[9]