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Clinical data
ATC code
  • None
Pharmacokinetic data
Elimination half-life12–18 hours[1]
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.230.713 Edit this at Wikidata
Chemical and physical data
Molar mass343.417 g/mol g·mol−1
3D model (JSmol)

6β-Naltrexol, or 6α-hydroxynaltrexone, is a major active metabolite of naltrexone formed by hepatic dihydrodiol dehydrogenase which acts as a potent, peripherally selective opioid neutral antagonist.[2][3] Relative to naltrexone, 6β-naltrexol has about half the affinity for the μ-opioid receptor,[1] but is present at approximately 10–30-fold higher concentrations at steady state due to extensive first-pass metabolism of the parent drug.[4] 6β-Naltrexol was itself investigated as an opioid antagonist, specifically for the treatment of opioid-induced constipation, and was found to be effective and well-tolerated, but was not further pursued.[2]

See also


  1. ^ a b Reginald Dean; Edward J. Bilsky; S. Stevens Negus (12 March 2009). Opiate Receptors and Antagonists: From Bench to Clinic. Springer Science & Business Media. pp. 269–. ISBN 978-1-59745-197-0.
  2. ^ a b Howard S. Smith (21 February 2013). Opioid Therapy in the 21st Century. Oxford University Press. pp. 69–. ISBN 978-0-19-984497-5.
  3. ^ Charles J. Cote; Jerrold Lerman; Brian J. Anderson (2013). A Practice of Anesthesia for Infants and Children: Expert Consult - Online and Print. Elsevier Health Sciences. pp. 148–. ISBN 1-4377-2792-1.
  4. ^ Mellar P. Davis; Paul A. Glare; Janet Hardy (28 May 2009). Opioids in Cancer Pain. Oxford University Press. pp. 41–. ISBN 978-0-19-923664-0.