Opioids: Difference between revisions

An '''opioid''' is any psychoactive chemical that resembles [[morphine]] or other opiates in its pharmacological effects. Opioids work by binding to [[Opioid receptor|opioid receptors]], which are found principally in the central and peripheral nervous system and the gastrointestinal tract.{{citation needed}} The receptors in these organ systems mediate both the beneficial effects and the side effects of opioids.

Although the term opiate is often used as a synonym for opioid, the term opiate is limited to drugs derived from the natural alkaloids found in the resin of the opium poppy (''Papaver somniferum'')<ref>{{Cite book|url=https://books.google.com/books?id=s8CXrbimviMC&pg=PA268|title=Pharmacology and Physiology for Anesthesia: Foundations and Clinical Application: Expert Consult - Online and Print|last=Hemmings|first=Hugh C.|last2=Egan|first2=Talmage D.|publisher=Elsevier Health Scienc,es|year=2013|isbn=1437716792|page=253|language=en|quote=Opiate is the older term classically used in pharmacology to mean a drug derived from opium. Opioid, a more modern term, is used to designate all substances, both natural and synthetic, that bind to opioid receptors (including antagonists).}}</ref>. While opioid is a more general term for substances that act primarily on opioid receptors, including natural occurring alkaloids, synthetic substances and opioid peptides <ref name=":17">{{Cite book|url=https://books.google.com/books?id=s8CXrbimviMC&pg=PA268|title=Pharmacology and Physiology for Anesthesia: Foundations and Clinical Application: Expert Consult - Online and Print|last=Hemmings|first=Hugh C.|last2=Egan|first2=Talmage D.|publisher=Elsevier Health Sciences|year=2013|isbn=1437716792|page=253|language=en|quote=Opiate is the older term classically used in pharmacology to mean a drug derived from opium. Opioid, a more modern term, is used to designate all substances, both natural and synthetic, that bind to opioid receptors (including antagonists).}}</ref>.

Opioid dependence can develop with ongoing administration, leading to a withdrawal syndrome with abrupt discontinuation.<ref>Cammarano, W. B., Pittet, J. F., Weitz, S., Schlobohm, R. M., & Marks, J. D. (1998). Acute withdrawal syndrome related to the administration of analgesic and sedative medications in adult intensive care unit patients. Critical care medicine, 26(4), 676-684.</ref> Opioids are not only well known for their addictive properties, but also for their ability to produce a feeling of euphoria, motivating some to use opioids recreationally.

Opioids are based upon [[morphine]] and opium-like structures. They work via their similar chemical structures to the endogenous opioids in the body. Morphine derived opioids, known as morphinans, contain a benzene ring attached to two partially unsaturated cyclohexane rings (phenanthrene) and a 4th nitrogenous ring attached to the core at carbons 9 and 13. There are several classes of opioids which differ greatly in structure from each other. For example, [[fentanyl]] and its analogues are structurally unique from [[morphinans]] and [[tramadol]] derivaties.

Opioids are known to mimic endogenous endorphins. Endorphins are responsible for analgesia (reducing pain), causing sleepiness, and feelings of pleasure. They can be released in response to pain, strenuous exercise, orgasm, or excitement.{{citation needed}} This mimicking of natural endorphins results in the drug's [[Physical euphoria|euphoric]], [[Pain relief|analgesic]] (pain relief) and [[Anxiety suppression|anxiolytic]] (anti-anxiety) effects.

Opioids act on the three main classes of [[opioid receptor]] in the nervous system, μ, κ, δ (mu, kappa, and delta). Each opioid is measured by its [[agonist]]ic or [[antagonist]]ic effects towards the receptors, with the responses to the different receptor sub-types (e.g., μ1 and μ2) providing even more effects. Opioid receptors are found mainly within the brain, but also within the spinal cord and digestive tract. {{citation needed}}

The delta receptor is responsible for the [[analgesia]], antidepressant and convulsant effects as well as physical dependence.{{citation needed}}

The kappa receptor is responsible for the [[analgesia]], [[anticonvulsant]], [[dissociative]] and [[deliriant]] effects as well as dysphoria, neuroprotection and [[sedation]].{{citation needed}}

The mu receptor is responsible for [[analgesia]], physical dependence, [[respiratory depression]], [[euphoria]], and possible [[vasodilation]].{{citation needed}}

The nociceptin receptor is responsible for [[anxiety]], [[depression]], appetite and development of tolerance to μ agonists.{{citation needed}}

====='''Zetta (ζ)'''=====

The zetta opioid receptor, also known as opioid growth factor receptor (OGFr) is responsible for tissue growth, neural development, and is further implicated in the development in some cancers. The endogenous ligand for OGFr is met-enkephalin, which is also a powerful endogenous delta opioid receptor agonist.{{citation needed}}

<h3 class="panel-header">'''Physical effects''' [[File:Child.svg|x20px|right|link=]]</h3>

 

*'''[[Physical euphoria|Euphoria]]''' - This sensation can be described as extreme feelings of intense physical comfort, warmth, and all-encompassing bliss.

*'''[[Pain relief|Pain relief]]'''

*'''[[Itchiness|Itchiness]]'''

*'''[[Constipation|Constipation]]'''

*'''[[Cough suppression|Cough suppression]]'''

*'''[[Effect::Decreased libido]]'''

*'''[[Difficulty urinating|Difficulty urinating]]'''

*'''[[Nausea|Nausea]]'''

*'''[[Stomach cramps|Stomach cramps]]'''

*'''[[Sedation|Sedation]]'''

*'''[[Pupil constriction|Pupil constriction]]'''

<h3 class="panel-header">'''Cognitive effects''' [[File:User.svg|x20px|right|link=]]</h3>

 

*'''[[Cognitive euphoria|Euphoria]]''' - This can be described as a powerful and overwhelming feeling of emotional bliss, contentment, and happiness.

*'''[[Motivation enhancement|Motivation enhancement]]''' - Some opioids (such as [[kratom]]) are more stimulating than others and seem to enhance motivation.

*'''[[Anxiety suppression|Anxiety suppression]]'''

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<h3 class="panel-header">'''Visual effects''' [[File:Eye.svg|x20px|right|link=]]</h3>

 

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==Pharmacological classes==

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In non-chronic use of safe dosages of opioids, physical and neurological toxicity are markedly safe.{{citation needed}}

Long term use of opioids causes hormonal imbalance in both men and women.<ref>The effect of opioid therapy on endocrine function. (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/23414717</ref>  

In men, this opioid-induced androgen decificeny essentially means that a long-term male opioid user will produce less than normal amounts of sex hormones – especially testosterone.<ref>Opioid-induced androgen deficiency (OPIAD). (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/22786453</ref>

This negative change in endocrine function in males can lead to:

A long term male user may also find more visual effects of their lowered testosterone such as:

The risk of fatal opioid overdoses rise sharply after a period of cessation and [[relapse]], largely because of reduced tolerance.<ref>Why Heroin Relapse Often Ends In Death - Lauren F Friedman (Business Insider) | http://www.businessinsider.com.au/philip-seymour-hoffman-overdose-2014-2</ref> To account for this lack of tolerance, it is safer to only dose a fraction of one's usual [[dosage]] if relapsing. It has also been found that the environment one is in can play a role in opioid tolerance. In one scientific study, rats with the same history of heroin administration were significantly more likely to die after receiving their dose in an environment not associated with the drug in contrast to a familiar environment.<ref>Siegel, S., Hinson, R., Krank, M., & McCully, J. (1982). Heroin “overdose” death: contribution of drug-associated environmental cues. Science, 216(4544), 436–437. https://doi.org/10.1126/science.7200260</ref>

*[[Depressants]]

*[[Extraction of opioids from painkiller products]]

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