Articles: narcotic-antagonists.
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Addiction to prescription opioids is prevalent in primary care settings. Increasing prescription opioid use is largely responsible for a parallel increase in overdose nationally. Many patients most at risk for addiction and overdose come into regular contact with primary care providers. ⋯ Similarly, through the use of screening and brief interventions, patients with addiction can achieve improved health outcome. A spectrum of low-threshold care options can reduce the negative health consequences among individuals with opioid addiction. Screening in primary care coupled with short interventions, including motivational interviewing, syringe distribution, naloxone prescription for overdose prevention, and buprenorphine treatment are effective ways to manage addiction and its associated risks and improve health outcomes for individuals with opioid addiction.
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The treatment of chronic pain, whether of cancer or noncancer origin, frequently involves the use of opioids. Delay in GI transit and constipation are the most common and often disabling side effects of opioid analgesics. ⋯ This goal is currently addressed by the use of opioid receptor antagonists with limited absorption such as oral naloxone and by the development of peripheral opioid receptor antagonists such as methylnaltrexone and alvimopan. These drugs hold considerable promise in preventing constipation due to treatments with opioids, whereas the analgesic action of opioids remains unabated.
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The reinforcing properties of nicotine may be mediated through release of various neurotransmitters both centrally and systemically. People who smoke report positive effects such as pleasure, arousal, and relaxation as well as relief of negative affect, tension, and anxiety. Opioid (narcotic) antagonists are of particular interest to investigators as potential agents to attenuate the rewarding effects of cigarette smoking. ⋯ Based on data from eight trials and over 1200 individuals, there was no evidence of an effect of naltrexone alone or as an adjunct to NRT on long-term smoking abstinence, with a point estimate strongly suggesting no effect and confidence intervals that make a clinically important effect of treatment unlikely. Although further trials might narrow the confidence intervals they are unlikely to be a good use of resources.
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Randomized Controlled Trial
Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing.
The current study tested the hypothesis that conditioned pain modulation is mediated by the release of endogenous opioids with a placebo-controlled (sugar pill) study of naltrexone (50 mg) in 33 healthy volunteers over two counter-balanced sessions. Pain modulation consisted of rating of heat pain (palm) during concurrent cold water immersion (foot). ⋯ An exploratory analysis revealed that individual differences in catastrophizing moderated the effects of naltrexone; endogenous opioid blockade abolished modulation in subjects lower in catastrophizing while modulation was unaffected by naltrexone among high catastrophizers. The results suggest a role of endogenous opioids in endogenous analgesia, but hint that multiple systems might contribute to conditioned pain modulation, and that these systems might be differentially activated as a function of individual differences in responses to pain.
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Fundam Clin Pharmacol · Jun 2013
Randomized Controlled TrialParacetamol and opioid pathways: a pilot randomized clinical trial.
Previous studies suggest that the antinociceptive action of paracetamol (acetaminophen, APAP) might involve descending inhibitory pain pathways and the opioidergic system: this study explores this issue in humans with naloxone, the opioid antagonist. After ethical approval, 12 healthy male volunteers were included in this randomized, controlled, double-blind, crossover, four-arm study. They were administered intravenous paracetamol (APAP 1 g) or saline (placebo, pl) followed at 100 min with IV naloxone (Nal 8 mg) or saline, every week for 4 weeks. ⋯ AUC (0-150) of APAP/pl is significantly different from pl/pl (-3452%.min (95%CI -4705 to -2199) vs. -933% min (95%CI -2273 to 407; P = 0.015) but not from APAP/Nal (-1731% min (95%CI -3676 to 214; P = 0.08) and other treatments. AUC (90-150) is not significantly different. This pilot study shows for the first time in human volunteers that naloxone does not inhibit paracetamol antinociception, suggesting no significant implication of the opioid system in paracetamol mechanism of action: this needs be confirmed on a larger number of subjects.