title: Transfer of interferon β-1a into human breastmilk.
abstract: OBJECTIVE
  This study determined the transfer of intramuscular interferon β-1a into human milk and provides an estimate of infant exposure to this antiviral in six women chronically receiving intramuscular interferon β-1a (Avonex(®), Biogen Idec, Research Triangle Park, NC).
  
  
  METHODS
  Interferon β-1a was measured at various times at steady state in milk samples collected from women receiving interferon β-1a at 30 μg/week.
  
  
  RESULTS
  Average milk concentrations were 46.7, 97.4, 66.4, 77.5, 103.1, 108.3, 124, and 87.9 pg/mL at 0, 1, 4, 8, 12, 24, 48, and 72 hours, respectively, after dosing. Using the highest value measured (179 pg/mL), the estimated relative infant dose would be 0.006% of the maternal dose.
  
  
  CONCLUSIONS
  These data clearly suggest that interferon β-1a does not penetrate the milk compartment significantly and that levels in milk are far subclinical. No side effects were noted in any of the breastfed infants.
authors: Department of Pediatrics, Texas Tech University School of Medicine, 1400 Coulter, Amarillo, TX 79106, USA. Thomas.Hale@ttuhsc.edu
authors: Thomas W
authors: TW
authors: Hale
authors: Afzal A
authors: AA
authors: Siddiqui
authors: Teresa E
authors: TE
authors: Baker
mesh_terms: D000276:Adjuvants, Immunologic / Q000009:adverse effects / Q000493:pharmacokinetics*; D000328:Adult; D001942:Breast Feeding / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007223:Infant; D007273:Injections, Intramuscular; D000068556:Interferon beta-1a; D016899:Interferon-beta / Q000009:adverse effects / Q000493:pharmacokinetics*; D007774:Lactation / Q000378:metabolism*; D008895:Milk, Human / Q000737:chemistry*; D009103:Multiple Sclerosis / Q000188:drug therapy*
chemical_list: D000276:Adjuvants, Immunologic; D016899:Interferon-beta; D000068556:Interferon beta-1a