
[NAL(TREXONE) + mefene (probably shortening and alteration of METHYLENE).]
Brand names: Revex
Chemical formula:

Nalmefene injection
What is nalmefene injection?
NALMEFENE (Revex®) reverses effects that are produced by narcotic drugs such as difficult breathing and coma. Narcotics may be used during surgery to help produce anesthesia and relieve pain, and nalmefene can reverse these effects after surgery. Nalmefene is used to treat cases of narcotic drug overdose. If you are dependent on narcotic drugs, nalmefene will cause withdrawal symptoms. Generic nalmefene injection is not available.What should I tell my health care provider before I take this medicine?
They need to know if you have any of these conditions:How should I use this medicine?
Nalmefene is for injection into a vein. Sometimes the injection may be given into a muscle or under the skin. It is given by a health-care professional in a hospital or clinic setting.What if I miss a dose?
This does not apply.What drug(s) may interact with nalmefene?
flumazenilWhat should I watch for while taking nalmefene?
Your condition will be monitored after you receive nalmefene.What side effects may I notice from receiving nalmefene?
Side effects given below are the result of reversal of narcotic therapy since nalmefene has little effect in the absence of narcotics.Where can I keep my medicine?
Keep out of the reach of children.Last updated: 7/1/2002
Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.
| Systematic (IUPAC) name | |
|---|---|
| 17-cyclopropylmethyl-4,5α-epoxy-6-methylenemorphinan-3,14-diol | |
| Clinical data | |
| AHFS/Drugs.com | monograph |
| MedlinePlus | a605043 |
| Pregnancy cat. | ? |
| Legal status | Prescription Only Medicine |
| Routes | Oral, Intravenous |
| Pharmacokinetic data | |
| Protein binding | 45% |
| Metabolism | hepatic |
| Half-life | 10.8 ± 5.2 hours |
| Excretion | renal |
| Identifiers | |
| CAS number | 55096-26-9 58895-64-0 (HCl) |
| ATC code | None |
| PubChem | CID 5284594 |
| ChemSpider | 4447642 |
| UNII | TOV02TDP9I |
| ChEMBL | CHEMBL982 |
| Chemical data | |
| Formula | C21H25NO3 |
| Mol. mass | 375.9 g/mol (hydrochloride) |
| SMILES | eMolecules & PubChem |
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Nalmefene (Revex), originally known as nalmetrene, is an opioid receptor antagonist developed in the early 1970s,[1] and used primarily in the management of alcohol dependence, and also has been investigated for the treatment of other addictions such as pathological gambling and addiction to shopping.
Nalmefene is an opiate derivative similar in both structure and activity to the opiate antagonist naltrexone. Advantages of nalmefene relative to naltrexone include longer half-life, greater oral bioavailability and no observed dose-dependent liver toxicity. As with other drugs of this type, nalmefene can precipitate acute withdrawal symptoms in patients who are dependent on opioid drugs, or more rarely when used post-operatively to counteract the effects of strong opioids used in surgery.
Nalmefene differs from naltrexone by substitution of the ketone group at the 6-position of naltrexone with a methylene (CH2) group, which considerably increases binding affinity to the μ-opioid receptor. Nalmefene also has high affinity for the other opioid receptors, and is known as a "universal antagonist" for its ability to block all three.
In clinical trials using this drug, doses used for treating alcoholism were in the range of 20-80 mg per day, orally.[2] The doses tested for treating pathological gambling were between 25-100 mg per day.[3] In both trials, there was little difference in efficacy between the lower and higher dosage regimes, and the lower dose (20 and 25 mg, respectively) was the best tolerated, with similar therapeutic efficacy to the higher doses and less side effects. Nalmefene is thus around twice as potent as naltrexone when used for the treatment of addictions.
Intravenous doses of nalmefene at between 0.5 to 1 milligram have been shown effective at counteracting the respiratory depression produced by opiate overdose [4], although this is not the usual application for this drug as naloxone is less expensive.
Doses of nalmefene greater than 1.5 mg do not appear to give any greater benefit in this application. Nalmefene's longer half-life might however make it useful for treating overdose involving longer acting opioids such as methadone, as it would require less frequent dosing and hence reduce the likelihood of renarcotization as the antagonist wears off.
Nalmefene is extensively metabolised in the liver, mainly by conjugation with glucuronic acid and also by N-dealkylation. Less than 5% of the dose is excreted unchanged. The glucuronide metabolite is entirely inactive, while the N-dealkylated metabolite has minimal pharmacological activity.
Lundbeck has licensed the drug from Biotie Therapeutics and performed clinical trials with nalmefene for treatment of alcohol-dependence.[5] In 2011 they submitted an application for their drug termed Selincro to the European Medicines Agency.[6] It has not been available on the US market since at least August 2008.
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