Opioid
Partial agonists, like the anti-diarrhea drug loperamide and antagonists, like naloxegol for opioid-induced constipation, do not cross the blood–brain barrier, but can displace other opioids from binding to those receptors in the myenteric plexus.[27] As an American legal term, narcotic refers to cocaine and opioids, and their source materials; it is also loosely applied to any illegal or controlled psychoactive drug.[35] For immediate relief of moderate to severe acute pain, opioids are frequently the treatment of choice due to their rapid onset, efficacy and reduced risk of dependence.[57] (The opioid analogue dextromethorphan, long claimed to be as effective a cough suppressant as codeine,[58] has similarly demonstrated little benefit in several recent studies.[63][64] However, findings from two recent systematic reviews of the literature found that opioids were not necessarily more effective in treating shortness of breath in patients who have advanced cancer.It is defined by the development of withdrawal symptoms when the substance is discontinued, when the dose is reduced abruptly or, specifically in the case of opioids, when an antagonist (e.g., naloxone) or an agonist-antagonist (e.g., pentazocine) is administered.[94] In European nations such as Austria, Bulgaria, and Slovakia, slow-release oral morphine formulations are used in opiate substitution therapy (OST) for patients who do not well tolerate the side effects of buprenorphine or methadone.[98][99] The amount of evidence available only permits making a weak conclusion, but it suggests that a physician properly managing opioid use in patients with no history of substance use disorder can give long-term pain relief with little risk of developing addiction, or other serious side effects.[70] Common adverse reactions in patients taking opioids for pain relief include nausea and vomiting, drowsiness, itching, dry mouth, dizziness, and constipation.Domperidone does not cross the blood–brain barrier and produce adverse central antidopaminergic effects, but blocks opioid emetic action in the chemoreceptor trigger zone.[112] The first mode of treatment is non-pharmacological, and includes lifestyle modifications like increasing dietary fiber, fluid intake (around 1.5 L (51 US fl oz) per day), and physical activity.[139] One study found that the depressed testosterone levels of heroin addicts returned to normal within one month of abstinence, suggesting that the effect is readily reversible and is not permanent.[146] Health care providers should not recommend that workers who drive or use heavy equipment including cranes or forklifts treat chronic or acute pain with opioids.[152] Infrequent adverse reactions in patients taking opioids for pain relief include: dose-related respiratory depression (especially with more potent opioids), confusion, hallucinations, delirium, urticaria, hypothermia, bradycardia/tachycardia, orthostatic hypotension, dizziness, headache, urinary retention, ureteric or biliary spasm, muscle rigidity, myoclonus (with high doses), and flushing (due to histamine release, except fentanyl and remifentanil).However, the elimination half-life of naloxone can be shorter than that of the opioid itself, so repeat dosing or continuous infusion may be required, or a longer acting antagonist such as nalmefene may be used.[201][202][203] Use of the opium poppy for medical, recreational, and religious purposes can be traced to the fourth century BC, when ideograms on Sumerians clay tablets mention the use of "Hul Gil", a "plant of joy".[210] The medical use of opium is later discussed by Pedanius Dioscorides (c. 40 – 90 AD), a Greek physician serving in the Roman army, in his five-volume work, De Materia Medica.[215] Opium became a major colonial commodity, moving legally and illegally through trade networks involving India, the Portuguese, the Dutch, the British and China, among others.Development of a glass syringe with a subcutaneous needle made it possible to easily administer controlled measurable doses of a primary active compound.[235] The first fully synthetic opioid was meperidine (Demerol), found serendipitously by German chemist Otto Eisleb (or Eislib) at IG Farben in 1932.[citation needed] In the United Kingdom the 1926 report of the Departmental Committee on Morphine and Heroin Addiction under the Chairmanship of the President of the Royal College of Physicians reasserted medical control and established the "British system" of control—which lasted until the 1960s.[246] In April 2019 the U.S. Food and Drug Administration announced the launch of a new education campaign to help Americans understand the important role they play in removing and properly disposing of unused prescription opioids from their homes.The "Remove the Risk" campaign is targeting women ages 35–64, who are most likely to oversee household health care decisions and often serve as the gatekeepers to opioids and other prescription medications in the home.The first scientific publication to use it, in 1963, included a footnote stating, "In this paper, the term, 'opioid', is used in the sense originally proposed by George H. Acheson (personal communication) to refer to any chemical compound with morphine-like activities".[272] Some minor opium alkaloids and various substances with opioid action are also found elsewhere, including molecules present in kratom, Corydalis, and Salvia divinorum plants and some species of poppy aside from Papaver somniferum.[275] It was discovered in 1953,[citation needed] that humans and some animals naturally produce minute amounts of morphine, codeine, and possibly some of their simpler derivatives like heroin and dihydromorphine, in addition to endogenous opioid peptides.7-Spiroindanyloxymorphone Acetylmorphone Codeinone Conorphone Codoxime Thebacon Hydrocodone Hydromorphone Metopon Morphinone N-Phenethyl-14-Ethoxymetopon Oxycodone Oxymorphone Pentamorphone Semorphone Chloromorphide 14-Hydroxydihydrocodeine Acetyldihydrocodeine Dihydrocodeine Nalbuphine Nicocodeine Nicodicodeine Oxymorphazone 1-IodomorphineAlazocine Bremazocine Dezocine Ketazocine Metazocine Pentazocine Phenazocine Cyclazocine 4-Fluoromeperidine Allylnorpethidine Anileridine Benzethidine Carperidine Difenoxin Diphenoxylate Etoxeridine Furethidine Hydroxypethidine Morpheridine Oxpheneridine Pethidine Pheneridine Phenoperidine Piminodine Properidine Sameridine Allylprodine α-Meprodineα-Prodine Prosidol Trimeperidine Acetoxyketobemidone Droxypropine Ketobemidone Methylketobemidone Propylketobemidone Alvimopan Loperamide Picenadol Dipipanone Methadone Normethadone Phenadoxone Dimepheptanol Levacetylmethadol Dextromoramide Levomoramide Racemoramide Diethylthiambutene Dimethylthiambutene Ethylmethylthiambutene Piperidylthiambutene Pyrrolidinylthiambutene Thiambutene Tipepidine Dextropropoxyphene Dimenoxadol Dioxaphetyl butyrate Levopropoxyphene Norpropoxyphene Diampromide Phenampromide Propiram Methiodone Isoaminile Lefetamine3-Allylfentanyl 3-Methylfentanyl 3-Methylthiofentanyl 4-Phenylfentanyl Alfentanil α-Methylacetylfentanyl α-Methylfentanyl α-Methylthiofentanyl β-Hydroxyfentanyl β-Hydroxythiofentanyl β-Methylfentanyl Brifentanil Carfentanil Fentanyl Lofentanil Mirfentanil Ocfentanil Ohmefentanyl Parafluorofentanyl Phenaridine Remifentanil Sufentanil Thiofentanyl Trefentanil Ethoheptazine Metheptazine Metethoheptazine Proheptazine Bezitramide Piritramide Clonitazene Etonitazene
Drug classmorphineATC codeMode of actionOpioid receptoropium poppyopioid receptorsopiatealkaloidPapaver somniferumpain reliefanesthesiadiarrheaopioid use disordersuppressing coughnaloxoneopioid overdosecarfentanilveterinaryrecreationallyeuphoricwithdrawalexecutions in the United Statesitchinesssedationnausearespiratory depressionconstipationeuphoriatolerancephysical dependenceaddictionoverdosedepressant drugsbenzodiazepinescentralperipheral nervous systemgastrointestinal tractpsychoactivePartial agonistsloperamideantagonistsnaloxegolblood–brain barriermyenteric plexuscontrolled substancesover-prescriptionof opioid medicationsheroinOpiatesalkaloidssemi-synthetic and synthetichydrocodoneoxycodonefentanylendogenous peptidesendorphinsnarcoticcocainecodeinewithout a prescriptionpalliative carerheumatoid arthritiscancer painheadachesback painfibromyalgiaparacetamolibuprofennaproxenmigraineneuropathic painchronic painnerve painmigrainesnonsteroidal anti-inflammatory drugsPercocetVicoprofenboosts the pain reliefcough suppressantsplacebotrialsdextromethorphanirritable bowel syndromeperipherally selectiveshortness of breathmethadonerestless legs syndromeOpioid-induced hyperalgesiaItchingDrowsinessDry mouthOpioid dependenceDizzinessLoss of appetiteDelayed gastric emptyingImpaired sexual functionDecreased testosterone levelsImmunodeficiencyIncreased pain sensitivityIrregular menstruationSlowed breathingaspiringastrointestinal bleedingkidney toxicityosteoarthritisneuroadaptationsreceptor upregulationmiosiscalcium channel blockersintrathecalmagnesiumNMDA antagonistsketaminememantinecholecystokinin antagonistsproglumidephosphodiesterase inhibitoribudilastpentazocinedysphoriasweatingrhinorreatremormyalgiahalf-life