Drug Levels and Effects:

Summary of Use during Lactation:

Limited information indicates that usual doses of nefazodone produce low but variable levels in milk that would not be expected to cause adverse effects in a breastfed infant, especially if the infant is older than 2 months. However, adverse effects in a breastfed preterm infant have been reported. If nefazodone is required by the mother of an older infant, it is not a reason to discontinue breastfeeding, but until more data become available, other drugs may be preferred, especially while nursing a newborn or preterm infant.

Drug Levels:

Nefazodone is metabolized to 4 metabolites, but only hydroxynefazodone is thought to be active as an antidepressant. Its antidepressant activity is considered to be equal to that of nefazodone.[1]

Maternal Levels.

The trough milk levels of nefazodone and its metabolites were measured 10 to 15 hours after the previous dose in 3 women who had been taking nefazodone for at least 3 weeks. Dosages were 200 mg twice daily, 50 mg twice daily, and for the third, 50 mg in the morning and 100 mg in the evening. Milk nefazodone levels were 57, 687, and 213 mcg/L, respectively; milk hydroxynefazodone was not quantifiable (<50 mcg/L) in the first 2 mothers and 104 mcg/L in the third.[2] Using the trough milk level data, the estimated minimum intake of these infants would be 0.24, 6.2 and 2% of the maternal weight-adjusted dosage of nefazodone and its active metabolite.

In another paper by the same authors, it appears that 2 of the above mothers were studied again in more detail. One mother who was 21 weeks postpartum had been taking nefazodone 50 mg in the morning and 100 mg in the evening for 6 days. The other mother who was 4 weeks postpartum had been taking nefazodone 200 mg twice daily for 7 months. Four or 5 milk levels were analyzed for drug and metabolites, but values do not appear in the published paper. No metabolites appeared in the milk of the first mother; only nefazodone and hydroxynefazodone were found in the milk of the second mother. The authors estimated that the first infant would receive 0.28 mg/kg daily or 0.4% of the maternal weight-adjusted dosage and the second would receive 0.54 mg/kg daily or 2.2% of the maternal weight-adjusted dosage.[3]

A woman was taking nefazodone 200 mg in the morning and 100 mg in the evening. The highest milk levels of nefazodone occurred 1 to 3 hours after the morning dose, with the highest level of 358 mcg/L occurring 3 hours after the dose. Hydroxynefazodone levels were consistently much lower with a peak level of 32 mcg/L at 2 hours after the dose. The authors estimated that an exclusively breastfed infant would receive 0.34% of the maternal weight-adjusted dosage of nefazodone and its active metabolite with this maternal dosage regimen. Two inactive metabolites would contribute an additional 0.11% of maternal dosage.[4]

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

Drowsiness, lethargy, poor feeding and low body temperature occurred in a 2.1 kg breastfed 9-week-old infant who was born preterm at 27 weeks to a mother taking a dose of 300 mg of nefazodone daily. The symptoms were probably caused by nefazodone in breastmilk.[4]

Possible Effects on Lactation:

Relevant published information was not found as of the revision date.

Alternate Drugs to Consider:



1. Weissman AM, Levy BT, Hartz AJ et al. Pooled analysis of antidepressant levels in lactating mothers, breast milk, and nursing infants. Am J Psychiatry. 2004;161:1066-78. PMID:15169695
2. Dodd S, Buist A, Burrows GD et al. Determination of nefazodone and its pharmacologically active metabolites in human blood and breast milk by high-performance liquid chromatography. J Chromatogr B Biomed Sci Appl. 1999;730:249-55. PMID:10448960
3. Dodd S, Maguire KP, Burrows GD et al. Nefazodone in the breast milk of nursing mothers: a report of two patients. J Clin Psychopharmacol. 2000;20:717-8. Letter. PMID:11106156
4. Yapp P, Ilett KF, Kristensen JH et al. Drowsiness and poor feeding in a breast-fed infant: association with nefazodone and its metabolites. Ann Pharmacother. 2000;34:1269-72. PMID:11098340

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antidepressants

  • Antidepressants, Second-Generation

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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