Articles: narcotic-antagonists.
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The results from animal studies suggest that opioid antagonists may prevent the reinforcing effects of alcohol consumption. Based on the results of those animal studies, some opioid antagonists, such as, naltrexone, nalmefene, have been studied for their benefits in treating alcohol dependence. ⋯ NTX at the dose of 50 mg/day is effective for alcohol dependence in short-term treatment. The optimal duration of NTX treatment may be longer than 3 months. The evidence so far may be too little to support the superiority of NTX to acamprosate and the inferiority of NTX to disulfiram. NTX treatment should be concurrently given with a psychosocial intervention. Other patterns of NTX administration should not be used at present, e.g., a dose of three times a week, combined NTX with other biological treatments. NMF has no role for the treatment of alcohol dependence in clinical practice. Randomised, double-blind, placebo-controlled trials of NTX treatment in patients with alcohol dependence are still needed. Some issues should be concerned in further studies. Firstly, further trials should be conducted in larger sample sizes and over longer periods of time. Secondly, other than the outcomes relevant to alcohol use, some important outcomes should also be measured, e.g., functioning, health-related quality of life, economic cost. Thirdly, the comparisons between NTX and other treatments for alcohol dependence, both biological and psychosocial, should be investigated. Fourthly, combined treatments of NTX and other biological treatments for alcohol dependence may be in issue of interest. Lastly, high discontinuation rate in both treatment and control groups should be concerned.
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Comparative Study Clinical Trial Controlled Clinical Trial
Blockade of hydromorphone effects by buprenorphine/naloxone and buprenorphine.
Buprenorphine is an opioid agonist-antagonist used in the treatment of opioid dependence. Naloxone has been combined with buprenorphine to decrease the parenteral abuse potential of buprenorphine. This addition of naloxone may also confer further opioid blockade efficacy. ⋯ The addition of naloxone to buprenorphine may deter the parenteral abuse of buprenorphine/naloxone, but it does not enhance the therapeutic efficacy of buprenorphine. The blockade efficacy of buprenorphine/naloxone is dose related; however, doses up to 32/8 mg buprenorphine/naloxone provide only partial blockade when subjects receive a high dose of an opioid agonist.
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J. Pharmacol. Exp. Ther. · Jan 2002
Randomized Controlled Trial Clinical TrialEffects of subcutaneous methylnaltrexone on morphine-induced peripherally mediated side effects: a double-blind randomized placebo-controlled trial.
Methylnaltrexone, the first peripheral opioid receptor antagonist, has the potential to prevent or reverse opioid-induced peripherally mediated side effects without affecting analgesia. In previous human trials, we demonstrated that intravenous methylnaltrexone prevented morphine-induced delay in gastrointestinal transit time. We also observed that the compound decreased some of the morphine-induced troublesome subjective effects. ⋯ In addition, subcutaneous methylnaltrexone significantly decreased morphine-induced subjective rating changes. Pharmacokinetic data after subcutaneous drug injection were compared to the data obtained from previous intravenous and oral administrations. Our results suggest that subcutaneous methylnaltrexone may have clinical utility in treating opioid-induced constipation and reducing opioid-induced unpleasant subjective symptoms.
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Naloxone is a medication that is frequently administered in the field by paramedics for suspected opioid overdoses. Most prehospital protocols, however, require this medication to be given to patients intravenously (i.v.) or intramuscularly (i.m.). Unfortunately, intravenous line placement may be problematic and time-consuming in chronic i.v. drug users. There may also be a delay in patient response to opioid reversal with i.m. absorption of naloxone. Additionally, routine use of needles in high-risk populations poses an increased risk of occupational blood exposures to paramedics. ⋯ Intranasal naloxone may provide a safe, rapid, effective way to manage suspected opioid overdoses in the field. Use of this route may decrease paramedic exposures to blood-borne diseases. The addition of i.n. naloxone administration to prehospital protocols should be considered as an initial therapy for suspected opioid abusers.
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Buprenorphine, a long-acting opioid with both agonist and antagonist properties, binds to mu-opioid (OP(3)), kappa-opioid (OP(2)), delta-opioid (OP(1)), and nociceptin (ORL-1) receptors. Its actions at these receptors have not been completely characterized, although buprenorphine is generally regarded as a mu-opioid receptor partial agonist and a kappa-opioid receptor antagonist. ⋯ Because of its partial agonist activity at mu-opioid receptors and its long half-life, buprenorphine has proven to be an excellent alternative to methadone for either maintenance therapy or detoxification of the opioid addict. Although buprenorphine may ultimately prove to be superior to methadone in the maintenance of the pregnant addict, its effects on the developing fetus must be carefully evaluated.