Drug Levels and Effects:

Summary of Use during Lactation:

Linezolid is excreted into breastmilk in concentration likely to be effective against staphylococcal strains found in mastitis.[1][2] Limited data indicate that the maximum dose an infant would receive through breastmilk would be much less than the standard infant dose.

If linezolid is required by the mother, it is not a reason to discontinue breastfeeding. Monitor the infant for possible effects on the gastrointestinal tract, such as diarrhea, vomiting, and candidiasis (e.g., thrush, diaper rash). However, because there is no published experience with linezolid during breastfeeding, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.

Drug Levels:

Maternal Levels.

A 32-year-old lactating woman was given a single dose of 600 mg of linezolid orally. Milk samples were taken at 10 time points over the next 24 hours. The peak concentration of linezolid in breastmilk occurred 2 hours after the dose with a value of 12.4 mg/L. Milk concentrations fell with a half-life of 6.5 hours and were detectable up to 24 hours after the dose.[2] Using the peak milk level data from this patient, an exclusively breastfed infant would receive an estimated maximum of about 2 mg/kg daily with the maximum recommended maternal dosage. The established maximum dose of linezolid for infants is 30 mg/kg daily.

Infant Levels.

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

Effects in Breastfed Infants:

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

Possible Effects on Lactation:

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

Alternate Drugs to Consider:



1. Delgado S, Arroyo R, Jimenez E et al. Staphylococcus epidermidis strains isolated from breast milk of women suffering infectious mastitis: potential virulence traits and resistance to antibiotics. BMC Microbiol. 2009;9:82. PMID:19422689
2. Sagirli O, Onal A, Toker S, Oztunc A. Determination of linezolid in human breast milk by high-performance liquid chromatography with ultraviolet detection. J AOAC Int. 2009;92:1658-62. PMID:20166583

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • -Infective Agents

  • Anti
  • -Bacterial Agents

  • 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.