Naltrexone Nalmefene

Pharmacology Nalmefene, an opioid antagonist, is a 6-methylene analog of naltrexone. Nalmefene prevents or reverses the effects of opioids, including respiratory depression, sedation, and hypotension. Nalmefene has no opioid agonist activity it does not produce respiratory depression, psychotomimetic effects or pupillary constriction, and no pharmacological activity was observed when it was administered in the absence of opioid agonists. Nalmefene can produce acute withdrawal symptoms in individuals who are opioid-dependent. 

Naltrexone, nalmefene Like naloxone but longer durations of action (10+ h) naltrexone is used in maintenance programs and can block heroin effects for up to 48 h ... 

Another agent of this general type is nalmefene (47) Despite their useful characteristics, opiates display tolerance, addiction, abuse, and some toxic side effects Antagonists combat some of these effects, most notably respiratory depression and addiction Nalmefene reputedly has significant oral activity as a narcotic antagonist The synthesis of nalmefine concludes by Wittig olefination of naltrexone (46) to nalmefene (47) This molecular transformation resulted in a significant increase in oral potency as well (141... 

Opioidergic agents. Naltrexone and nalmefene, opioid antagonists with no intrinsic agonist properties, have been studied for the treatment of alcohol dependence. Naltrexone has been studied much more extensively than nalmefene for this indication. In 1984 naltrexone was approved by the FDA for the treatment of opioid dependence, and in 1994 it was approved for the treatment of alcohol dependence. Nalmefene is approved in the United States as a parenteral formulation for the acute reversal of opioid effects (e.g., after opioid overdose or analgesia). 

Nabazenil, 209 Naboctate, 209 Nafimidone, 90 Naflocort, 75 Nafoxidine, 65 Naftifme, 55 Nalmefene, 62 Naltrexone, 62 Napamezole, 87 Narcotic antagonist, 62 Nedocromil, 8 Nefazodone, 98 Neflumozide, 133 Netobimin, 36 Neuromuscular blocker, 69 Nifedipine, 106 Nilvadipine, 107 Nisoxetine, 30 Nitromifene, 65 Nizatidine, 95 Nomifensine, 146... 

Opium and opiate, and any salt, compound, derivative, or preparation of opium or opiate excluding apomorphine, thebaine-derived butorphanol, dextror-phan, nalbuphine, nalmefene, naxolone, and naltrexone, and their respective salts, but including the following ... 

In summary, naltrexone and perhaps other opioid antagonists such as nalmefene are promising agents in the pharmacotherapy of alcohol dependence with or without coexisting psychiatric and addictive disorders (418). 

Naltrexone and nalmefene are structurally related to naloxone. Naltrexone is the /V-cyclopropy I methyl analogue of oxymorphone while nalmefene is the /V-allyl analogue. They have similar pharmacological properties to naloxone but with longer durations of action, with elimination half-lives in excess of 8 hours. They also have significant oral availability. They are used mainly in the management of addicts. 

The pure opioid antagonist drugs naloxone,naltrexone, and nalmefene are morphine derivatives with bulkier substituents at the l l17 position. These agents have a relatively high affinity for - opioid binding sites. They have lower... 

A number of narcotic antagonists based on the morphinan stmcture have been marketed—for example, Buprenorphine, Naloxone, Naltrexone, and Nalorfine. Nalmefene is being pursued for the treatment of alcohol abuse. Oxycodone, and its precursor Codeine, are marketed, with restrictions, as analgesics. noSee Chapter 9, Table 3. 

Another universal antagonist is the naltrexone-derived nalmefene (14). This 6-methylene derivative of naltrexone shows higher k opioid receptor affinity [51, 52], Nalmefene is a potent, orally active opioid antagonist with a... 

Nalmefene can be synthesized by a Wittig reaction of naltrexone with tri-phenylphosphonium bromide in dimethyl sulphoxide with sodium hydride as base [57],... 

Nalmefene is a pure opioid antagonist, which is structurally similar to naloxone and naltrexone. 

Activated charcoal is the preferred method of decontamination. The use of syrup of ipecac is contraindicated because of the potential for serious CNS and respiratory depression. Naloxone, a specific opioid antagonist, should be used to reverse significant respiratory depression. Nalmefene and naltrexone are... 

Drobes DJ, Anton RF, Thomas SE, Voronin K (2004) Effects of naltrexone and nalmefene on subjective response to alcohol among non-treatment-seeking alcoholics and social drinkers. Alcohol Clin Exp Res 28 1362-1370... 

Antidotes opioid antagonists nalmefene naloxone naltrexone... 

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