Articles: narcotic-antagonists.
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Biomed. Chromatogr. · May 2000
High-performance liquid chromatographic determination of naltrexone in plasma of hemodialysis patients.
A simple, sensitive, selective and reliable reversed-phase high-performance liquid chromatographic (HPLC) method with UV detection is described for the determination of naltrexone in plasma samples. Naltrexone and the internal standard, naloxone, were isolated from plasma either with a liquid-liquid extraction method using ethyl acetate or with a solid-phase extraction method using Sep-Pack C18 cartridge before chromatography. The extracts were dried under a stream of nitrogen and the samples were reconstituted in the mobile phase, then 20 microL were injected on a Waters Symmetry C18 column (5 microm particle size, 4.6 x 150 mm). ⋯ The present method was applied to the determination of the plasma concentration of naltrexone in dialyzed patients. Patients (n = 8) with severe generalized pruritus received 50 mg of naltrexone orally per day for 2 weeks. The variability in the therapeutic response in treated patients required plasma concentration investigations of this opioid antagonist.
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Clinical Trial
Maximum tolerated dose of nalmefene in patients receiving epidural fentanyl and dilute bupivacaine for postoperative analgesia.
This study investigated the ability of the modified continual reassessment method (MCRM) to determine the maximum tolerated dose of the opioid antagonist nalmefene, which does not reverse analgesia in an acceptable number of postoperative patients receiving epidural fentanyl in 0.075% bupivacaine. ⋯ The modified continual reassessment method facilitated determination of the maximum tolerated dose ofnalmefene . Operating characteristics of the modified continual reassessment method suggest it may be an effective statistical tool for dose-finding in trials of selected analgesic or anesthetic agents.
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Clin. Pharmacol. Ther. · Apr 2000
Randomized Controlled Trial Comparative Study Clinical TrialEffects of enteric-coated methylnaltrexone in preventing opioid-induced delay in oral-cecal transit time.
Methylnaltrexone is the first peripheral opioid receptor antagonist. It has the potential to prevent or reverse the peripherally mediated gastrointestinal effects of opioids. In previous human volunteer trials, we demonstrated that oral uncoated methylnaltrexone prevented morphine-induced delay in gastrointestinal transit time. ⋯ Our results suggest that there is a prevailing direct and local luminal effect of enteric-coated methylnaltrexone and that the enteric-coated formulation exerts its gut pharmacologic actions more efficiently than the uncoated formulation.
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Critical care medicine · Apr 2000
Randomized Controlled Trial Comparative Study Clinical TrialAcute detoxification of opioid-addicted patients with naloxone during propofol or methohexital anesthesia: a comparison of withdrawal symptoms, neuroendocrine, metabolic, and cardiovascular patterns.
Mu-Opioid receptor blockade during general anesthesia is a new treatment for detoxification of opioid addicted patients. We assessed catecholamine plasma concentrations, oxygen consumption, cardiovascular variables, and withdrawal symptoms after naloxone and tested the hypothesis that variables are influenced by the anesthetic administered during detoxification. ⋯ Naloxone treatment, in opioid-addicted patients, induced a marked increase in catecholamine plasma concentrations, metabolism, and cardiovascular stimulation during anesthesia with both propofol and methohexital. Although both anesthetics appear suitable for detoxification treatment, the use of propofol is associated with earlier extubation and, surprisingly, a shortened period of long-term withdrawal symptoms during detoxification.
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Comparative Study Clinical Trial Controlled Clinical Trial
Effects of buprenorphine versus buprenorphine/naloxone tablets in non-dependent opioid abusers.
Buprenorphine is an opioid agonist-antagonist under development in the United States as a sublingual medication for treatment of opioid dependence. Buprenorphine may be abused; therefore, tablets combining buprenorphine with naloxone have been developed with the intent of reducing the abuse risk in people physically dependent upon opioids. The characteristics and abuse potential of buprenorphine and buprenorphine/naloxone tablets in non-dependent opioid abusers have not been determined. Non-parenteral abuse of opioids such as buprenorphine may be more likely in people who have less severe substance abuse disorders (e.g., are not physically dependent upon opioids). ⋯ These results suggest that sublingual buprenorphine and buprenorphine/naloxone may both be abused by opioid users who are not physically dependent upon opioids.