Clinical data | |
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Trade names | Revex, others |
Other names | Nalmetrene; 6-Desoxy-6-methylenenaltrexone; CPH-101; JF-1; Lu AA36143; NIH-10365; ORF-11676 |
AHFS/Drugs.com | Monograph |
MedlinePlus | a605043 |
License data | |
Routes of administration | By mouth, intranasal, intramuscular, intravenous, subcutaneous |
Drug class | Opioid antagonist |
ATC code | |
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Pharmacokinetic data | |
Bioavailability | 40–50% (orally) [7] |
Protein binding | 45% |
Metabolism | Liver |
Elimination half-life | 10.8 ± 5.2 hours |
Excretion | Kidney |
Identifiers | |
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PubChem CID | |
IUPHAR/BPS | |
DrugBank |
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ChemSpider | |
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KEGG | |
ChEBI | |
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CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.164.948 |
Chemical and physical data | |
Formula | C21H25NO3 |
Molar mass | 339.435 g·mol−1 |
3D model (JSmol) | |
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Nalmefene, sold under the brand name Revex among others, is a medication that is used in the treatment of opioid overdose and alcohol dependence. [2] [3] Nalmefene belongs to the class of opioid antagonists and can be taken by mouth, administered by injection, or delivered through nasal administration. [8]
In terms of its chemical structure and biological activity, nalmefene is similar to another opioid antagonist called naltrexone, as they are both derivatives of opiates. However, nalmefene offers certain advantages over naltrexone. These include a longer elimination half-life, which means it stays in the body for a longer duration, improved absorption when taken by mouth, and no observed liver toxicity that is dependent on the dosage. [9]
Nalmefene is available as a generic medication. [10]
Intravenous doses of nalmefene have been shown effective at counteracting the respiratory depression produced by opioid overdose. [3]
Nalmefene is used in the European Union to reduce alcohol dependence [2] and NICE recommends the use of nalmefene to reduce alcohol consumption in combination with psychological support for people who drink heavily. [11]
Based on a meta analysis, the usefulness of nalmefene for alcohol dependence is unclear. [12] Nalmefene, in combination with psychosocial management, may decrease the amount of alcohol drunk by people who are alcohol dependent. [12] [13] The medication may also be taken "as needed", when a person feels the urge to consume alcohol. [13]
The following side effects of nalmefene are very common (≥10% incidence):
The following side effects of nalmefene are common (≥1% to <10% incidence):
The majority of these reactions were mild or moderate, associated with treatment initiation, and of short duration. [14]
Affinities (Ki ) | Ratios | Refs | ||
---|---|---|---|---|
MOR | KOR | DOR | MOR:KOR:DOR | |
0.24 nM | 0.083 nM | 16 nM | 3:1:193 | [15] [16] |
0.3 nM | 0.3 nM | 7.3 nM | 1:1:24 | [17] [18] |
Nalmefene acts as an inverse agonist of the μ-opioid receptor (MOR) (Ki = 0.24 nM) and as a weak partial agonist (Ki = 0.083 nM; Emax = 20–30%) of the κ-opioid receptor (KOR), with similar binding for these two receptors but a several-fold preference for the KOR. [15] [16] In another study however, nalmefene had approximately equal affinity for the MOR and KOR. [17] [18] In vivo evidence indicative of KOR activation, such as elevation of serum prolactin levels due to dopamine suppression and increased hypothalamic–pituitary–adrenal axis activation via enhanced adrenocorticotropic hormone and cortisol secretion, has been observed in humans and animals. [15] [19] Side effects typical of KOR activation such as hallucinations and dissociation have also been observed with nalmefene in human studies. [20] It is thought that nalmefene activation of KOR may produce dysphoria and anxiety. [21] In addition to MOR and KOR binding, nalmefene also possesses some, albeit far lower affinity for the δ-opioid receptor (DOR) (Ki = 16 nM), where it behaves as an antagonist. [15] [16] [22]
Nalmefene is structurally related to naltrexone and differs from it by substitution of the ketone group at the C6 position of naltrexone with a methylene group (CH2). It binds to the MOR with similar affinity relative to naltrexone, but binds "somewhat more avidly" to the KOR and DOR in comparison. [15] [19]
Nalmefene with a single 1 mg dose by intravenous injection has been found to produce brain MOR blockade of 99% at 5 minutes, 90% at 2 hours, 33% at 4 hours, and 10% at 8 hours. [23] A lower dose of 1 μg/kg intravenously resulted in brain MOR blockade of 52% at 5 minutes, 33% at 2 hours, 47% at 4 hours, and 26% at 8 hours. [23] With oral administration, peak brain MOR occupancy of 87 to 100% was found after 3 hours with single or repeated dosing of nalmefene. [24] [25] At 26 hours (1.1 days) post-administration, brain MOR occupancy was 83 to 100%; at 50 hours (2.1 days), it was 48 to 72%; and at 74 hours (3.1 days), it was 12 to 46%. [24] [25] The half-time of nalmefene occupancy of brain MORs is about 29 hours and is much longer than with naloxone. [24] [26] Substantial brain MOR occupancy occurs with nalmefene even when blood levels of nalmefene are very low. [24] [25] The prolonged brain MOR occupancy of nalmefene may be due to slow dissociation of nalmefene from MORs consequent to its high MOR affinity. [24] [25]
Nalmefene is extensively metabolized 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.[ citation needed ]
Nalmefene is a derivative of naltrexone and was first reported in 1975. [27]
Nalmefene was first reported in a patent in 1974. [28]
In the United States, immediate-release injectable nalmefene was approved in 1995, as an antidote for opioid overdose. [29] It was sold under the brand name Revex. [3] The product was discontinued by its manufacturer around 2008. [30] [31] [32] A generic version was approved for medical use in the United States in February 2022. [10] [33]
In May 2023, the Food and Drug Administration (FDA) approved a nalmefene hydrochloride nasal spray, under the brand name Opvee, for the emergency treatment of opioid overdose in people aged twelve years of age and older. [34]
In August 2024, the FDA approved a nalmefene hydrochloride auto-injector (Zurnai) for the emergency treatment of known or suspected opioid overdose in people aged twelve years of age and older. [5] [35] The FDA granted the application for the nalmefene hydrochloride auto-injector fast track and priority review designations. [35] The FDA granted approval of Zurnai to Purdue Pharma L.P. [35]
As of 2012, nalmefene in pill form, used for the treatment of alcohol dependence and other addictive behaviors, is not available in the United States. [9]
Danish pharmaceutical company Lundbeck has licensed nalmefene from Biotie Therapies and performed clinical trials with nalmefene for treatment of alcohol dependence. [36] In 2011, they submitted an application for their medication named Selincro to the European Medicines Agency. [37] The medication was authorized for use in the EU in March 2013. [38] and in October 2013, Scotland became the first country in the EU to prescribe the drug for alcohol dependence. [39] England followed Scotland by offering the medication as a treatment for problem drinking in October 2014. [40] In November 2014, nalmefene was approved as a possible treatment supplied by Britain's National Health Service (NHS) for reducing alcohol consumption in people with alcohol dependence. [41]
Oral nalmefene was under development for the treatment of pathological gambling, interstitial cystitis, pruritus, rheumatoid arthritis, shock, and smoking withdrawal, but development was discontinued for all of these indications. [42] Formulations of nalmefene for use by intramuscular injection, intravenous injection, and intranasal administration are in late-stage development for the treatment of opioid-related disorders. [43] [44]
Nalmefene might be useful to treat cocaine addiction. [45]
Oxycodone, sold under the brand name Roxicodone and OxyContin among others, is a semi-synthetic opioid used medically for treatment of moderate to severe pain. It is highly addictive and is a commonly abused drug. It is usually taken by mouth, and is available in immediate-release and controlled-release formulations. Onset of pain relief typically begins within fifteen minutes and lasts for up to six hours with the immediate-release formulation. In the United Kingdom, it is available by injection. Combination products are also available with paracetamol (acetaminophen), ibuprofen, naloxone, naltrexone, and aspirin.
Naloxone is an opioid antagonist: a medication used to reverse or reduce the effects of opioids. For example, it is used to restore breathing after an opioid overdose. Effects begin within two minutes when given intravenously, five minutes when injected into a muscle, and ten minutes as a nasal spray. Naloxone blocks the effects of opioids for 30 to 90 minutes.
Tramadol, sold under the brand name Ultram among others, is an opioid pain medication and a serotonin–norepinephrine reuptake inhibitor (SNRI) used to treat moderately severe pain. When taken by mouth in an immediate-release formulation, the onset of pain relief usually begins within an hour. It is also available by injection. It is available in combination with paracetamol (acetaminophen).
Opioid use disorder (OUD) is a substance use disorder characterized by cravings for opioids, continued use despite physical and/or psychological deterioration, increased tolerance with use, and withdrawal symptoms after discontinuing opioids. Opioid withdrawal symptoms include nausea, muscle aches, diarrhea, trouble sleeping, agitation, and a low mood. Addiction and dependence are important components of opioid use disorder.
Buprenorphine, sold under the brand name Subutex among others, is an opioid used to treat opioid use disorder, acute pain, and chronic pain. It can be used under the tongue (sublingual), in the cheek (buccal), by injection, as a skin patch (transdermal), or as an implant. For opioid use disorder, the patient must have moderate opioid withdrawal symptoms before buprenorphine can be administered under direct observation of a health-care provider.
Oxymorphone is a highly potent opioid analgesic indicated for treatment of severe pain. Pain relief after injection begins after about 5–10 minutes, after oral administration it begins after about 30 minutes, and lasts about 3–4 hours for immediate-release tablets and 12 hours for extended-release tablets. The elimination half-life of oxymorphone is much faster intravenously, and as such, the drug is most commonly used orally. Like oxycodone, which metabolizes to oxymorphone, oxymorphone has a high potential to be abused.
Baclofen, sold under the brand name Lioresal among others, is a medication used to treat muscle spasticity such as from a spinal cord injury or multiple sclerosis. It may also be used for hiccups and muscle spasms near the end of life, and off-label to treat alcohol use disorder or opioid withdrawal symptoms. It is taken orally or by intrathecal pump. It is also sometimes used transdermally in combination with gabapentin and clonidine prepared at a compounding pharmacy.
Naltrexone, sold under the brand name Revia among others, is a medication primarily used to manage alcohol use or opioid use disorder by reducing cravings and feelings of euphoria associated with substance use disorder. It has also been found effective in the treatment of other addictions and may be used for them off-label. An opioid-dependent person should not receive naltrexone before detoxification. It is taken orally or by injection into a muscle. Effects begin within 30 minutes, though a decreased desire for opioids may take a few weeks to occur.
Nalbuphine, sold under the brand names Nubain among others, is an opioid analgesic which is used in the treatment of pain. It is given by injection into a vein, muscle, or fat.
An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors.
The κ-opioid receptor or kappa opioid receptor, abbreviated KOR or KOP for its ligand ketazocine, is a G protein-coupled receptor that in humans is encoded by the OPRK1 gene. The KOR is coupled to the G protein Gi/G0 and is one of four related receptors that bind opioid-like compounds in the brain and are responsible for mediating the effects of these compounds. These effects include altering nociception, consciousness, motor control, and mood. Dysregulation of this receptor system has been implicated in alcohol and drug addiction.
Lofexidine, sold under the brand name Lucemyra among others, is a medication historically used to treat high blood pressure; today, it is more commonly used to help with the physical symptoms of opioid withdrawal. It is taken by mouth. It is an α2A-adrenergic receptor agonist. It was approved for use by the Food and Drug Administration in the United States in 2018.
Diprenorphine, also known as diprenorfin, is a non-selective, high-affinity, weak partial agonist of the μ- (MOR), κ- (KOR), and δ-opioid receptor (DOR) which is used in veterinary medicine as an opioid antagonist. It is used to reverse the effects of super-potent opioid analgesics such as etorphine and carfentanil that are used for tranquilizing large animals. The drug is not approved for use in humans.
Nalfurafine is an antipruritic that is marketed in Japan for the treatment of uremic pruritus in individuals with chronic kidney disease undergoing hemodialysis. It activates the κ-opioid receptor (KOR) and is potent, selective, and centrally active. It was the first selective KOR agonist approved for clinical use. It has also been dubiously referred to as the "first non-narcotic opioid drug" in history.
Tapentadol, sold under the brand name Nucynta among others, is an opioid analgesic of the benzenoid class with a dual mode of action as an agonist of the μ-opioid receptor and as a norepinephrine reuptake inhibitor (NRI). Analgesia occurs within 32 minutes of oral administration, and lasts for 4–6 hours.
An opioid overdose is toxicity due to excessive consumption of opioids, such as morphine, codeine, heroin, fentanyl, tramadol, and methadone. This preventable pathology can be fatal if it leads to respiratory depression, a lethal condition that can cause hypoxia from slow and shallow breathing. Other symptoms include small pupils and unconsciousness; however, its onset can depend on the method of ingestion, the dosage and individual risk factors. Although there were over 110,000 deaths in 2017 due to opioids, individuals who survived also faced adverse complications, including permanent brain damage.
Samidorphan is an opioid antagonist that in the form of olanzapine/samidorphan is used in the treatment of schizophrenia and bipolar disorder. Samidorphan reduces the weight gain associated with olanzapine. Samidorphan is taken by mouth.
Buprenorphine/naloxone, sold under the brand name Suboxone among others, is a fixed-dose combination medication that includes buprenorphine and naloxone. It is used to treat opioid use disorder, and reduces the mortality of opioid use disorder by 50%. It relieves cravings to use and withdrawal symptoms. Buprenorphine/naloxone is available for use in two different forms, under the tongue or in the cheek.
Buprenorphine/naltrexone is an experimental combination drug formulation of buprenorphine, a μ-opioid receptor (MOR) weak partial agonist and κ-opioid receptor (KOR) antagonist, and naltrexone, a MOR and KOR silent antagonist, which is under investigation for the potential treatment of psychiatric disorders. The combination of the two drugs is thought to result in a selective blockade of the KOR and hence fewer MOR activation-related concerns such as euphoria and opioid dependence. It has been found to produce antidepressant-like effects in mice and has recently been found to be effective in the treatment of cocaine dependence in a large clinical trial.
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