Drug Levels and Effects:

Summary of Use during Lactation:

In the United States and other developed countries, HIV-infected mothers should generally not breastfeed their infants. In countries in which no acceptable, feasible, sustainable and safe replacement feeding is available, exclusive breastfeeding for 6 months is recommended for HIV-infected mothers to reduce the risk of HIV transmission from the mother to the infant compared with mixed feeding.[1][2][3][4][5][6] In these settings, abrupt weaning at 4 months does not reduce the risk of HIV transmission or produce an overall health benefit compared to continued breastfeeding, and increases the risk of infant death in HIV-infected infants.[7] Extended antiretroviral prophylaxis in breastfed infants with antiretroviral drugs appears to reduce the rate of HIV transmission during breastfeeding by about half, but the optimal regimen and duration of prophylaxis has not yet been defined.[8][9][10][11] Limited information in this setting indicates that efavirenz produces low levels in milk and no adverse reactions in breastfed infants however, alternate antiretroviral agents are generally preferred.

Drug Levels:

Maternal Levels.

Thirteen mothers who averaged 15.8 weeks (range 6 to 25 weeks) postpartum were treated with efavirenz 600 mg daily plus zidovudine and lamivudine. Milk and plasma samples were taken 3 to 4 hours after the last dose. Skimmed breastmilk efavirenz concentrations averaged 3.5 mg/L (range 1.3 to 7.4 mg/L).[12]

Infant Levels.

Thirteen mothers who averaged 15.8 weeks (range 6 to 25 weeks) postpartum were treated with efavirenz 600 mg daily plus lamivudine and zidovudine (n = 12) or stavudine (n = 1). Plasma samples were taken from their breastfed infants 3 to 4 hours after the last dose. Infant plasma concentrations averaged 0.86 mg/L (range 0.4 to 1.5 mg/L). Infant plasma concentrations averaged 13% of maternal plasma concentrations, but there was no statistically significant correlation between them. Average plasma levels were slightly below the plasma level considered effective for suppression of HIV in adults.[12]

Effects in Breastfed Infants:

Thirteen mothers nursed their infants while they were taking efavirenz 600 mg daily, lamivudine 150 mg and zidovudine 300 mg daily (n = 12) or stavudine 60 mg daily (n = 1) . No adverse reactions were reported in the infants after 6 months of breastfeeding, none had developed HIV infection and all were developing normally.[12]

Possible Effects on Lactation:

Gynecomastia has been reported among men and at least one woman receiving efavirenz therapy.[13][14] Efavirenz appears to be much more likely to cause gynecomastia than other antiretroviral agents. Gynecomastia is unilateral initially, but can progress to bilateral. Spontaneous resolution usually occurred within one year, even with continuation of the regimen.

The relevance of these findings to nursing mothers is not known. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider:



1. World Health Organization. HIV and infant feeding: update. 2007.
2. Dao H, Mofenson LM, Ekpini R et al. International recommendations on antiretroviral drugs for treatment of HIV-infected women and prevention of mother-to-child HIV transmission in resource-limited settings: 2006 update. Am J Obstet Gynecol. 2007;197 (3 Suppl):S42-55. PMID:17825650
3. Branson BM, Handsfield HH, Lampe MA et al. Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings. MMWR Recomm Rep. 2006;55 (RR-14):1-17. PMID:16988643
4. McIntyre J, Dabis F, Mofenson LM et al. Rapid advice: Use of antiretroviral drugs for treating pregnant women and preventing HIV infection in infants. World Health Organization. Geneva. 2009;1-23.
5. Chasela CS, Hudgens MG, Jamieson DJ et al. Maternal or infant antiretroviral drugs to reduce HIV-1 transmission. N Engl J Med. 2010;362:2271-81. PMID:20554982
6. Shapiro RL, Hughes MD, Ogwu A et al. Antiretroviral regimens in pregnancy and breast-feeding in Botswana. N Engl J Med. 2010;362:2282-94. PMID:20554983
7. Kuhn L, Aldrovandi GM, Sinkala M et al. Effects of early, abrupt weaning on HIV-free survival of children in Zambia. N Engl J Med. 2008;359:130-41. PMID:18525036
8. Kumwenda NI, Hoover DR, Mofenson LM et al. Extended antiretroviral prophylaxis to reduce breast-milk HIV-1 transmission. N Engl J Med. 2008;359:119-29. PMID:18525035
9. Mofenson LM. Antiretroviral prophylaxis to reduce breast milk transmission of HIV type 1: new data but still questions. J Acquir Immune Defic Syndr. 2008;48:237-40. PMID:18545160
10. Bedri A, Gudetta B, Isehak A et al. Extended-dose nevirapine to 6 weeks of age for infants to prevent HIV transmission via breastfeeding in Ethiopia, India, and Uganda: an analysis of three randomised controlled trials. Lancet. 2008;372:300-13. PMID:18657709
11. Chigwedere P, Seage GR, Lee TH, Essex M. Efficacy of antiretroviral drugs in reducing mother-to-child transmission of HIV in Africa: a meta-analysis of published clinical trials. AIDS Res Hum Retroviruses. 2008;24:827-37. PMID:18544018
12. Schneider S, Peltier A, Gras A et al. Efavirenz in human breast milk, mothers', and newborns' plasma. J Acquir Immune Defic Syndr. 2008;48:450-4. PMID:18614925
13. Jover F, Cuadrado JM, Roig P et al. Efavirenz-associated gynecomastia: report of five cases and review of the literature. Breast J. 2004;10:244-6. PMID:15125753
14. Rahim S, Ortiz O, Maslow M, Holzman R. A case-control study of gynecomastia in HIV-1-infected patients receiving HAART. AIDS Read. 2004;14:23-4, 29-32, 35-40. PMID:14959701

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antiinfective Agents

  • Anti
  • -HIV Agents

  • Antiviral Agents

  • Anti
  • -Retroviral Agents

  • Reverse Transcriptase
  • Inhibitors

    Administrative Information:

    LactMed Record Number:


    Last Revision Date:

    Disclaimer:Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.