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Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Naloxone, sold under the brand name Narcan among others, is a medication used to block the effects of opioids, especially in overdose. Naloxone may be combined within the same pill as an opioid to decrease the risk of misuse. When given intravenously, it works within 2 min, and when injected into a muscle, it works within 5 min. The medication may also be used in the nose. The effects of naloxone last about half an hour to an hour. Multiple doses may be required, as the duration of action of most opioids is greater than that of naloxone. Fentanyl has been found in busts involving heroin, morphine, oxycodone and hydrocodone. It has also been found in cocaine and synthetic marijuana, also known as “spice.” Law enforcement personnel and drug-sniffing dogs are at risk from exposure to synthetic opioids. Many response organizations that may have to deal with synthetic opioids carry Narcan with them in the event of exposure.
Common Sense Emergency Response
Published in Robert A. Burke, Common Sense Emergency Response, 2020
Naloxone, sold under the brand name Narcan among others, is a medication used to block the effects of opioids, especially in overdose. Naloxone may be combined within the same pill as an opioid to decrease the risk of misuse. When given intravenously, it works within 2 min, and when injected into a muscle, it works within 5 min. The medication may also be used in the nose. The effects of naloxone last about half an hour to an hour. Multiple doses may be required as the duration of action of most opioids is greater than that of naloxone. Fentanyl has been found in busts involving heroin, morphine, oxycodone, and hydrocodone. It has also been found in cocaine and synthetic marijuana aka “Spice.” Law enforcement personnel and drug-sniffing dogs are at risk from exposure to synthetic opioids. Many response organizations that may have to deal with synthetic opioids carry Narcan with them in the event of an exposure.
Control of Postoperative Pain by Self-Administered Opioids
Published in Robert B. Northrop, Endogenous and Exogenous Regulation and Control of Physiological Systems, 2020
With the wide and specific distribution of endogenous opioids in the CNS and peripheral nervous system comes the necessary fact that there must also be a multiplicity of opioid receptors on these nerves. In the CNS there is evidence for at least four major types of opioid receptors, classified as μ, κ, δ, and σ. Undoubtedly, there are subclasses of these four classes. μ and κ receptors are associated with analgesia; however, not all receptors are associated with analgesia. Dysphoria and psychomimetic effects are associated with σ receptors in the limbic system of the CNS, and δ receptors may be involved with affective behavior.61 The situation is made more complex because of cross-talk between exogenous opioids caused by nonunique affinities to a given class of receptor. This crosstalk is illustrated by the fact that certain exogenous opioids can have agonist (Ag), partial agonist (pAg), or antagonist (Ant) action at certain receptor types. Table 9.1, adapted from Goodman and Gilman,61 illustrates some of these properties. Note that naloxone is the treatment of choice for opioid poisoning (as with morphine or heroin); it has no direct respiratory depressant action.
Incorporating methods and findings from neuroscience to better understand placebo and nocebo effects in sport
Published in European Journal of Sport Science, 2020
Christopher Beedie, Fabrizio Benedetti, Diletta Barbiani, Eleanora Camerone, Jacob Lindheimer, Bart Roelands
A model for this type of research can be found in a study of conditioned and expectation responses to real and placebo morphine in hand-grip muscle performance (Benedetti, Pollo, et al., 2007). Participants were randomly allocated to one of four groups: During a two week training phase, Groups A and B were given no morphine, whilst Groups C and D received intramuscular morphine one hour before each training session at a dose of 0.14 mg/kg. Groups C and D were also informed that an increase in pain tolerance was expected. In the training trials, ischemic arm pain was experimentally induced via a tourniquet technique in concert with a hand grip task. The authors argued that this type of ischemic pain increases over time very quickly, and the pain becomes unbearable after around 14 min. Following the training phase, and on what was termed to ‘competition day’, treatments administered to participants were as follows: NT during training phase: no-treatment (NT) on competition day. Assessed natural history;NT during training phase: Placebo saline solution via intramuscular injection plus a verbal suggestion of morphine on competition day. Assessed effects of expectancy;Morphine 0.14 mg/kg via intramuscular injection during training phase: Placebo saline solution via intramuscular injection plus a verbal suggestion of morphine on competition day. Assessed effects of conditioning;Morphine 0.14 mg/kg via intramuscular injection during training phase: Opiate antagonist naloxone by injection on competition day plus a verbal suggestion of morphine. Assessed opioid mechanisms of placebo effects.
Consensus statement on placebo effects in sports and exercise: The need for conceptual clarity, methodological rigour, and the elucidation of neurobiological mechanisms
Published in European Journal of Sport Science, 2018
Christopher Beedie, Fabrizio Benedetti, Diletta Barbiani, Eleanora Camerone, Emma Cohen, Damian Coleman, Arran Davis, Charlotte Elsworth-Edelsten, Elliott Flowers, Abby Foad, Simon Harvey, Florentina Hettinga, Philip Hurst, Andrew Lane, Jacob Lindheimer, John Raglin, Bart Roelands, Lieke Schiphof-Godart, Attila Szabo
Neurobiological mechanisms of placebo effects. In arguably a landmark study (Levine, Gordon, & Fields, 1978) it was demonstrated that the placebo effect on pain could be reversed by administration of the opiate antagonist naloxone. This finding suggested not only that the placebo effect in this context had a clear neurobiological mechanism, but that the mechanism of placebo analgesia was what would be expected with a real analgesic treatment. Since this publication, an extensive body of research has shown not only that expectation and conditioning independently cause placebo effects, but that each operate via discrete neurophysiological pathways. In fact, this research has shown that there is not just one mechanism of the placebo effect, but several, each operating across different neurobiological pathways. For example, in a study of pain (Amanzio & Benedetti, 1999), the placebo effects were either experimentally conditioned, or resulted from experimentally induced expectations (conditioning was achieved by means of either the opioid agonist morphine hydrochloride or the nonopioid ketorolac tromethamine). Expectation resulted in placebo responses that were completely blocked by the opioid antagonist naloxone, suggesting that the placebo effect in question was a function of opioid pathways. Expectation cues together with morphine conditioning also produced placebo responses that were completely blocked by naloxone, as did morphine conditioning alone. By contrast, ketorolac conditioning together with expectation cues elicited a placebo effect that was only partially blocked by naloxone, and ketorolac conditioning alone produced placebo responses that were naloxone-insensitive. Therefore, Amanzio and Benedetti elicited different types of placebo responses using different methods of induction, conditioning and expectation. These data and findings of many other studies (for review see Benedetti & Dogue, 2015) indicate that placebo effects can be intact neurophysiological events, the mechanisms of which vary in relation to contextual cues, ultimately affecting activity in endogenous self-regulatory systems. These are proposals that could, and perhaps should, be tested in sport and exercise, especially given that many of the variables examined in placebo effect research in neuroscience and elsewhere, such as pain, fatigue, and oxygen availability, have implications for both.