Norbuprenorphine is a major

active metabolite An active metabolite is an active form of a drug after it has been processed by the body. Metabolites of drugs An active metabolite results when a drug is metabolized by the body into a modified form which continues to produce effects in the body ...

of the

opioid modulator An opioid modulator (or opioid receptor modulator) is a drug which has mixed agonist and antagonist actions at different opioid receptors and thus cannot clearly be described as either an opioid ''agonist'' or ''antagonist''. An example of an opio ...

buprenorphine Buprenorphine is an opioid used to treat opioid use disorder, acute pain, and chronic pain. It can be used under the tongue (sublingual), in the cheek (buccal), by injection (intravenous and subcutaneous), as a skin patch (transdermal ...

. It is a μ-opioid, δ-opioid, and nociceptin receptor

full agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the a ...

, and a

κ-opioid receptor The κ-opioid receptor or kappa opioid receptor, abbreviated KOR or KOP, is a G protein-coupled receptor that in humans is encoded by the ''OPRK1'' gene. The KOR is coupled to the G protein Gi/G0 and is one of four related receptors that bind ...

partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist. They may also be considered ligands which display both agonistic and antagonis ...

. In rats, unlike buprenorphine, norbuprenorphine produces marked

respiratory depression Hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate (''hypo'' meaning "below") to perform needed respiratory gas exchange. By definition it causes an increased concentration of carbon dioxide (hypercapni ...

but with very little antinociceptive effect. In explanation of these properties, norbuprenorphine has been found to be a high affinity

P-glycoprotein P-glycoprotein 1 (permeability glycoprotein, abbreviated as P-gp or Pgp) also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) or cluster of differentiation 243 (CD243) is an important protein ...

substrate, and in accordance, shows very limited blood-brain-barrier penetration. Buprenorphine 2

References

4,5-Epoxymorphinans Phenols Tertiary alcohols Ethers Kappa-opioid receptor agonists Mu-opioid receptor agonists Delta-opioid receptor agonists Nociceptin receptor agonists Opioid metabolites Peripherally selective drugs {{nervous-system-drug-stub

See also

References