Mirtazapine

The Basics

What is Mirtazapine?

Mirtazapine is an antidepressant.

Brand names for Mirtazapine

Remeron

How Mirtazapine is classified

Antidepressive Agents, Antidepressive Agents (Second-Generation)

Mirtazapine During Pregnancy

Mirtazapine pregnancy category

Category CNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Mirtazapine while pregnant

Can you take mirtazapine while pregnant? Reproduction studies in pregnant rats and rabbits at doses up to 100 mg/kg and 40 mg/kg, respectively [20 and 17 times the maximum recommended human dose (MRHD) on an mg/m² basis, respectively], have revealed no evidence of teratogenic effects. However, in rats, there was an increase in postimplantation losses in dams treated with mirtazapine. There was an increase in pup deaths during the first 3 days of lactation and a decrease in pup birth weights. The cause of these deaths is not known. The effects occurred at doses that were 20 times the MRHD, but not at 3 times the MRHD, on an mg/m² basis. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Taking Mirtazapine While Breastfeeding

What are recommendations for lactation if you're taking Mirtazapine?

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.

Maternal / infant drug levels

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.

Possible effects of Mirtazapine on milk supply

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.[7]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.[8] 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.[9] 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.[10]

Possible alternatives to Mirtazapine

Nortriptyline, Paroxetine, Sertraline.