Nalmefene for alcohol dependence: a NICE decision?

Nalmefene Hydrochloride: Potential Implications for Treating Alcohol and Opioid Use Disorder

Nalmefene hydrochloride was first discovered as an opioid antagonist derivative of naltrexone in 1975. It is among the most potent opioid antagonists currently on the market and is differentiated from naloxone and naltrexone by its partial agonist activity at the kappa-opioid receptor which may benefit in the treatment of alcohol use disorder. Oral nalmefene has been approved in the European Union for treatment of alcohol use disorder since 2013. As of 2023, nalmefene is available in the United States as an intranasal spray for reversal of opioid overdose but is not approved for alcohol or opioid use disorder as a maintenance treatment. The substantially longer half-life of nalmefene and 5-fold higher binding affinity to opioid receptors makes it a superior agent over naloxone in the reversal of high potency synthetic opioids like fentanyl and the emerging nitazenes. Nalmefene presents with a comparable side effect profile to other opioid antagonists and should be considered for further development as a maintenance treatment for opioid and other substance use disorders.

Economic evaluations of alcohol pharmacotherapy: Systematic review of economic evaluations of pharmacotherapy for the treatment of alcohol use disorder

OBJECTIVE

Alcohol use disorders confer a significant burden of disease and economic cost worldwide. However, the utilisation of pharmacotherapies to manage alcohol use disorder is poor. We aimed to conduct a systematic review of economic evaluation studies of alcohol use disorder pharmacotherapies.

METHODS

A search was conducted in Embase, Medline, CINAHL, PsychINFO and EconLit (August 2019, updated September 2022). Full economic evaluations using pharmacotherapy to treat alcohol use disorders were included. Included studies were stratified by medication and summarised descriptively. The Consensus on Health Economic Criteria list was used to assess the methodological quality.

RESULTS

A total of 1139 studies were retrieved, of which 15 met the inclusion criteria. All studies were conducted in high-income countries. Four studies analysed nalmefene, four studies assessed acamprosate, three for naltrexone and four for stand-alone and/or combinations of naltrexone and acamprosate. There were 21 interventions synthesised from 15 studies as some studies evaluated multiple interventions and comparators. More than half of the included studies (73%) reported pharmacotherapy as dominant (less costly and more effective than comparators). From healthcare payer perspectives, five studies found that pharmacotherapy added to psychosocial support was dominant or cost-effective, accruing additional benefits at a higher cost but under accepted willingness to pay thresholds. Three analyses from a societal perspective found pharmacotherapy added to psychosocial support was a dominant or cost-effective strategy. Quality scores ranged from 63% to 95%.

CONCLUSION

Pharmacotherapy added to psychosocial support was cost-effective from both healthcare and societal perspectives, emphasising an increased role for pharmacotherapy to reduce the burden of alcohol use disorders.

Novel Agents for the Pharmacological Treatment of Alcohol Use Disorder

Alcohol use disorder (AUD) is a highly prevalent but severely under-treated disorder, with only three widely-approved pharmacotherapies. Given that AUD is a very heterogeneous disorder, it is unlikely that one single medication will be effective for all individuals with an AUD. As such, there is a need to develop new, more effective, and diverse pharmacological treatment options for AUD with the hopes of increasing utilization and improving care. In this qualitative literature review, we discuss the efficacy, mechanism of action, and tolerability of approved, repurposed, and novel pharmacotherapies for the treatment of AUD with a clinical perspective. Pharmacotherapies discussed include: disulfiram, acamprosate, naltrexone, nalmefene, topiramate, gabapentin, varenicline, baclofen, sodium oxybate, aripiprazole, ondansetron, mifepristone, ibudilast, suvorexant, prazosin, doxazosin, N-acetylcysteine, GET73, ASP8062, ABT-436, PF-5190457, and cannabidiol. Overall, many repurposed and novel agents discussed in this review demonstrate clinical effectiveness and promise for the future of AUD treatment. Importantly, these medications also offer potential improvements towards the advancement of precision medicine and personalized treatment for the heterogeneous AUD population. However, there remains a great need to improve access to treatment, increase the menu of approved pharmacological treatments, and de-stigmatize and increase treatment-seeking for AUD.

Drinking Levels and Profiles of Alcohol Addicted Rats Predict Response to Nalmefene

Background: Pharmacotherapeutic options supporting the treatment of alcohol dependence are recommended and available but underutilized, partly due to questions about efficacy. Nalmefene, a μ-opioid receptor antagonist and partial kappa receptor agonist, is recommended for reduction of alcohol consumption, but evidence about its effectiveness has been equivocal; identifying factors which predict response will help optimize treatment.

Methods: The alcohol deprivation effect paradigm is a tightly controlled procedure comprising repeated deprivation and reintroduction phases, leading to increased preference for alcohol; reintroduction approximates relapse. Using a digital drinkometer system measuring high-resolution drinking behavior, we examined the effects of nalmefene on relapse drinking behavior in alcohol addicted rats. We also tested whether drinking behavior in the relapse phase prior to nalmefene administration predicted treatment response. We further examined whether longitudinal drinking behavior and locomotor activity predicted treatment response.

Results: Our results showed that nalmefene (0.3 mg/kg) reduced relapse-like consumption significantly (∼20%) compared to vehicle on the first 2 days of alcohol reintroduction. Examining the first 6 h of a preceded treatment-free relapse episode revealed drinking patterns clustering the rats into responders (reduction of >40%, n = 17) and non-responders (reduction of <40%, n = 7) to subsequent nalmefene treatment. During the first 6 h of the preceding relapse phase, responders consumed more alcohol than non-responders; the amount of alcohol consumed during each drinking approach was larger but frequency of drinking did not differ. Longitudinal drinking behavior and locomotor activity did not significantly predict response.

Conclusion: Our results suggest that nalmefene reduces alcohol intake during a relapse-like situation but effectiveness can differ greatly at the individual level. However, who responds may be informed by examining drinking profiles and rats that show high drinking levels prior to treatment are more likely to respond to nalmefene.

Diagnosis and Pharmacotherapy of Alcohol Use Disorder: A Review

Importance

Alcohol consumption is associated with 88 000 US deaths annually. Although routine screening for heavy alcohol use can identify patients with alcohol use disorder (AUD) and has been recommended, only 1 in 6 US adults report ever having been asked by a health professional about their drinking behavior. Alcohol use disorder, a problematic pattern of alcohol use accompanied by clinically significant impairment or distress, is present in up to 14% of US adults during a 1-year period, although only about 8% of affected individuals are treated in an alcohol treatment facility.

Observations

Four medications are approved by the US Food and Drug Administration to treat AUD: disulfiram, naltrexone (oral and long-acting injectable formulations), and acamprosate. However, patients with AUD most commonly receive counseling. Medications are prescribed to less than 9% of patients who are likely to benefit from them, given evidence that they exert clinically meaningful effects and their inclusion in clinical practice guidelines as first-line treatments for moderate to severe AUD. Naltrexone, which can be given once daily, reduces the likelihood of a return to any drinking by 5% and binge-drinking risk by 10%. Randomized clinical trials also show that some medications approved for other indications, including seizure disorder (eg, topiramate), are efficacious in treating AUD. Currently, there is not sufficient evidence to support the use of pharmacogenetics to personalize AUD treatments.

Conclusions and Relevance

Alcohol consumption is associated with a high rate of morbidity and mortality, and heavy alcohol use is the major risk factor for AUD. Simple, valid screening methods can be used to identify patients with heavy alcohol use, who can then be evaluated for the presence of an AUD. Patients receiving a diagnosis of the disorder should be given brief counseling and prescribed a first-line medication (eg, naltrexone) or referred for a more intensive psychosocial intervention.