Opioid classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Classification

Endogenous opioids

Opioid-peptides that are produced in the body include:

β-endorphin is expressed in Pro-opiomelanocortin (POMC) cells in the arcuate nucleus and in a small population of neurons in the brainstem, and acts through μ-opioid receptors. β-endorphin has many effects, including on sexual behavior and appetite. β-endorphin is also secreted into the circulation from pituitary corticotropes and melanotropes. α-neoendorphin is also expressed in POMC cells in the arcuate nucleus.

[met]-enkephalin is widely distributed in the CNS; [met]-enkephalin is a product of the proenkephalin gene, and acts through μ and δ-opioid receptors. [leu]-enkephalin, also a product of the proenkephalin gene, acts through δ-opioid receptors.

Dynorphin acts through κ-opioid receptors, and is widely distributed in the CNS, including in the spinal cord and hypothalamus, including in particular the arcuate nucleus and in both oxytocin and vasopressin neurons in the supraoptic nucleus.

Endomorphin acts through μ-opioid receptors, and is more potent than other endogenous opioids at these receptors.

Opium alkaloids

Phenanthrenes naturally occurring in opium:

Preparations of mixed opium alkaloids, including papaveretum, are still occasionally used.

Semisynthetic derivatives

Synthetic opioids

Anilidopiperidines

Phenylpiperidines

Diphenylpropylamine derivatives

Propoxyphene
Dextropropoxyphene
Dextromoramide
Bezitramide
Piritramide
Methadone
Dipipanone
Levo-alphacetylmethadol (LAAM)
Loperamide (used for diarrhoea, does not cross the blood-brain barrier)
Diphenoxylate (used for diarrhoea, does not appreciably cross the blood-brain barrier)

Benzomorphan derivatives

Oripavine derivatives

Morphinan derivatives

Others

Opioid antagonists

References

↑ Odell LR, Skopec J, McCluskey A. “Isolation and identification of unique marker compounds from the Tasmanian poppy Papaver somniferum N.” Forensic Sci Int (2007). PMID 17765420

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[Odell_2007-1] Odell LR, Skopec J, McCluskey A. “Isolation and identification of unique marker compounds from the Tasmanian poppy Papaver somniferum N.” Forensic Sci Int (2007). PMID 17765420

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