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Canada (161,798)
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PS268 (56)
Chapter 13

Drugs and Behaviour - Chapter 13

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Bruce Mc Kay

Drugs and Behaviour – Chapter 13  History of Opioids o Opium  Produced and available for collection for only few days of opium poppy’s life  Harvesting  Cut made into unripe seed pods, white substance oozes out, oxidizes to red-brown and scraped and collected into small balls  Early history of opium  Most likely origin is hot, dry, middle eastern country  Papaver somiferum produced substance that eased pain and suffering  Important in Greek medicine o Galen claimed it as a cure-all  Recreational use also common – opium cakes and candies sold everywhere on streets  Writers and opium: keys to paradise  1805 – Thomas De Quincey purchased laudanum and wrote “The confessions of an English Opium Eater”  Elizabeth Barrett Browning/Samuel Taylor Coleridge did as well  Opium changes way users perceives the world o Opium eater too happy to observe motion of time  De Quincey, for long periods unable to write due to opium dependence  The Opium Wars  Tobacco smoking spread much more rapidly  1644 – tobacco smoking forbade o Did not last long, but increased opium smoking  Smoking tobacco and eating opium existed side by side  Addiction of opium took edge off tobacco craving  Opium smoking resulted in rapid effect compared to oral use  1729 – opium shop owners strangled in China o Smuggling opium profitable for everyone  Before 1557 – Portuguese allowed to develop small trading post of Macao  Near end of 17 century – Canton Port opened under very strict rules  Profit British made from selling opium paid for tea shipped back to England  East India Company auctioned chests of opium cakes  Increased from 200 in 1729 to 25000 in 1838  Opium war started in 1839 o British given Hong Kong as victory o Posed moral dilemma for Britain o 1893 – moral protest against trade o 1906 – government support and bill passed in 1913 o Morphine  1805 – eased toothache and fell into abyss of divine enjoyment  Active agent 10x as potent as opium  Morphine – primary agent in opium  1832 – Codeine found –secondary active ingredient  Major increase of morphine use came as result of two nondrug developments  1853 – Development of hypodermic syringe o Faster delivery system into blood stream  American Civil War o Reduce pain and relief from dysentery Drugs and Behaviour – Chapter 13 o Heroin  Two acetyl groups attached to morphine, given brand name heroin  3x as potent as morphine  Effects are identical, more potent and acts faster  Perfect drug, more potent, less harmful  Originally used as substitute for codeine  Heroin could produce powerful dependence when injected in high doses o Opium and heroin supply, distribution and trafficking in Canada  Opium  Least potent of opiate family  Sold as powder or dark brown solid  Can be smoked, ingested or injected  2008 – opium consumption emerged as result of introduction of drug called dode o Grinding dried seed od into fine powder  Taken with tea or hot water  Produces quick high followed by sense of well-being  Rarely imported directly from one source, smuggled via transit countries  Continues to be supplied by organized crime groups  Heroin  Afghanistan – 83% of global heroin production in 2009  Believed to originate in south/southwest Asia  Heroin synthesis achieved through relative simple chemical process o Acetic anhydride less hazardous to users, rise in prices  2009 – 213 kg seized o Most common way to smuggle was using hollowed out objects  Mexican heroin is brown or black o Low prices, high purity  2006 – purity o Mexico – 30% o SA – 36%  1990s – increased purity of heroin allowed, snorting to produce effects helped reduce spread of AIDS and other diseases o Changing profile of opioid users  Illicit heroin use one of the central elements of high-risk street drug use  Upsurge involved increases in use and related harms of prescription opioid (PO) analgesics relative to heroin use  POs most prevalently misused form of opioids  Increasing prevalence of PO use in street-opioid-use  Substantial rise in medical use of prescription opioids and marked rise in nonmedical use  Increased medical uses accompanied by nonmedical uses o Increased opioid dependence and overdose  95% pure and openly sold in S. Vietnam, 5% purity in USA  Heroin sold in S. Vietnam inexpensive  1970s and 1980s  Late 1960s – US government several efforts to estimate heroin users  Impossible task to perform  No particular trends or patterns seen in data o Might be argued that no change occurred during this period o Abuse of prescription opioids in Canada  Oxycodone available as pain reliever known as Percocet or Percodan Drugs and Behaviour – Chapter 13  1996 – long acting dosage – OxyContin  Releases oxycodone into bloodstream over 12 hours  Taken less often because of long release time  Substantial comorbid pain, psychiatric symptoms and other psychoactive substance use problems  Pharmacology of the Opioids o Chemical and pharmacokinetic characteristics  Raw opium contains 10% morphine by weight and smaller amount of codeine  Acetyl groups allow heroin to penetrate blood-brain barrier  Heroin 2-3x more potent  Medicinal chemists separate analgesic effect from dependence-producing effects  Opioid antagonists – block action of morphine, heroin or other opioid agonists  Reverse effects of opioid overdose  Can produce immediate withdrawal effect o Mechanism of action  1970s – discovery of selective opioid receptors  Resulted in discovery of endorphins  1976s – opioid receptors not homogeneous, existence of opioid receptor types  Morphine and ketocyclazocine  1977 – deferens receptor discovered  Mu (Morphine)  Found in brainstem and medial thalamus  Responsible for supraspinal analgesia, respiratory depression, euphoria, sedation, decreased gastrointestinal motility and physical dependence  Kappa (Ketocyclazocine)  Found in limbic and diencephalic areas, brain stem, spinal cord, responsible for spinal analgesia, sedation, dyspnea, dependence, dysphoria and respiratory depression  Delta (Delta-alanine-delta-leucine-enkephalin)  Largely in brain and effects not well studied  May be responsible for psychotomimetic and dysphonic effects  Sigma (N-allylnormetazocine)  Responsible for psychomimetic effects, dysphoria and stress-induced depression  Inhibits GABA release  Allows dopaminergic neurons to fire more vigorously and extra dopamine intensely pleasurable  Enkephalins act like morphine and many times as potent  Endorphins found in brain tissue have potent opioid effects  Mu and kappa receptors play role in pain perception  Delta receptors not easily understood  Large amounts of endorphins released from pituitary gland in response to stress  Might not be capable of producing a high  Beneficial Uses of Opioids o Pain Relief  Major benefit is pain reduction  Reduces awareness to aversive effects of pain  Reduces emotional response to pain and knowledge of pain stimulus  Relatively specific to pain  Reduces pain without inducing sleep, but drowsiness is not uncommon o Intestinal Disorders  Quiet colic and save lives by counteracting diarrhea Drugs and Behaviour – Chapter 13  Decreases contraction responsible for moving food through intestines  Saved lives of many dysentery victim  Opium solution available for symptomatic diarrhea relief o Cough Suppressants  Decreases activity in cough control centre in medulla  Still available in wide variety of prescription cough remedies  Non-prescription contains dextromethorphan  High doses produces hallucinogenic effects through different mechanism  Causes for Concern o Dependence potential  Tolerance  Can occur at different rates for different effects  If used chronically, necessary to increase dosage to maintain constant effect  Tolerance to one reduces effectiveness of each of the others  With repeated experience, dependent person might unconsciously learn to anticipate those effects and to counteract them  Physical dependence  As each dose begins to wear off, certa
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