title: Transfer of linezolid into breast milk.
abstract: 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.
authors.affiliation: Lower Mainland Pharmacy Services, Surrey Memorial Hospital, Surrey, BC, Canada hilary.rowe@fraserhealth.ca.
authors.forename: Hilary E
authors.initials: HE
authors.lastname: Rowe
authors.affiliation: School of Medicine, Texas Tech University Health Sciences Center, Amarillo, TX, USA.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Felkins
authors.affiliation: School of Medicine, Texas Tech University Health Sciences Center, Amarillo, TX, USA.
authors.forename: Shaun D
authors.initials: SD
authors.lastname: Cooper
authors.affiliation: School of Medicine, Texas Tech University Health Sciences Center, Amarillo, TX, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Hale
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D019540:Area Under Curve; D001942:Breast Feeding; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D000069349:Linezolid / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008413:Mastitis / Q000097:blood / Q000188:drug therapy*; D055624:Methicillin-Resistant Staphylococcus aureus; D008895:Milk, Human / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D000069349:Linezolid
keywords: breast milk; breastfeeding; human milk; linezolid