Transfer of naltrexone and its metabolite 6,beta-naltrexol into human milk.
The excretion of naltrexone and its primary metabolite 6,beta-naltrexol in breast milk from a 30-year-old lactating opiate addict undergoing oral naltrexone pharmacotherapy (5 mg/d) was studied. Concentrations of naltrexone and 6,beta-naltrexol in serial milk and plasma samples taken over a 19.3-hour period of a dose interval at steady state were measured by gas chromatography. The calculated infant dose relative to the maternal weight was 0.03% for naltrexone and 0.83% (as naltrexone equivalents) for 6,beta-naltrexol. Total relative infant dose estimated for the complete 24-hour dose interval was 1.06%. Her 6-week-old breastfed infant was healthy, achieving expected milestones, and showed no adverse effects. Only 6,beta-naltrexol was detected in infant plasma and at a very low concentration of 1.1 micro g/L. Use of naltrexone during breastfeeding should be undertaken only after an individual risk benefit analysis.
Pharmacology Unit, School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia.
Carol F
CF
Chan
Madhu
M
Page-Sharp
Judith H
JH
Kristensen
George
G
O'Neil
Kenneth F
KF
Ilett
D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D007223:Infant; D007774:Lactation / Q000378:metabolism*; D008297:Male; D008895:Milk, Human / Q000737:chemistry*; D009271:Naltrexone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics*; D009292:Narcotic Antagonists / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*
D009292:Narcotic Antagonists; C010410:6 beta-hydroxynaltrexone; D009271:Naltrexone