Transfer of linezolid into breast milk

J Hum Lact. 2014 Nov;30(4):410-2. doi: 10.1177/0890334414546045. Epub 2014 Aug 6.


Linezolid, a broad-spectrum antibiotic used primarily for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections, is the first oxazolidinone approved for clinical use. This is a case report of a 30-year-old woman who was exclusively breastfeeding her infant prior to taking linezolid 600 mg orally every 12 hours to treat a MRSA mastitis. Breast milk samples were obtained over a 12-hour dosing interval on day 1 (after a single dose of therapy) and again on day 14 (at steady state). The relative infant dose at steady state was found to be 15.61% on day 14 of therapy. Using the average concentration at steady state, the estimated infant dose would have been 1.84 mg/kg/day, which is well below the recommended dose given to neonates requiring linezolid drug therapy. The infant did not breastfeed during maternal treatment with linezolid.

Keywords: breast milk; breastfeeding; human milk; linezolid.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / therapeutic use*
  • Area Under Curve
  • Breast Feeding*
  • Female
  • Humans
  • Infant, Newborn
  • Linezolid / administration & dosage
  • Linezolid / pharmacokinetics
  • Linezolid / therapeutic use*
  • Mastitis / blood
  • Mastitis / drug therapy*
  • Methicillin-Resistant Staphylococcus aureus*
  • Milk, Human / metabolism*


  • Anti-Bacterial Agents
  • Linezolid