Nalmefene for Alcohol Reduction: Uses, How It Works and Side Effects
Reviewed by Luciana D'Agnone BA, MSc | Director & Editorial Lead - Last reviewed: 15 October 2026
Nalmefene (brand name targetting alcohol intake reduction: Selincro) is a prescription medication used in the UK to help adults with alcohol dependence reduce their alcohol intake. Nalmefene is designed to be used alongside ongoing psychosocial support, it is not effective for detoxification purposes and it is not an anti-cravint tablet.
This article explains the patient profile appropriate for nalmefene treatment, how the drug works in the brain, how it should be administered, what the clinical evidence shows, and the main side effects and safety restrictions to be aware of before starting treatment.
Current, peer-reviewed research suggests that nalmefene can reduce heavy drinking days and total alcohol consumption over longer treatment periods (Chiang et al., 2024).
What is nalmefene and what is it used for?
In the UK, nalmefene is prescribed to help adults with alcohol dependence reduce how much they drink. According to NICE clinical recommendations, it is a viable option for individuals who continue to have a high risk of relapse approximately two weeks after an initial assessment, do not experience physical withdrawal symptoms, and do not require immediate detoxification.
Current UK clinical guidelines for alcohol treatment place nalmefene within a specific treatment pathway after detoxification and withdrawal phases from drinking episodes. It is one of several medications for alcohol dependence available to clinicians.
Who may be suitable for nalmefene?
Nalmefene is intended for individuals with a mild or patterned form of alcohol dependence who wish to cut down rather than stop completely. The initial two-week assessment period is essential because some individuals naturally reduce their drinking through monitoring and psychosocial support alone, making medication unnecessary.
An independent review by Palpacuer et al. (2015) notes that while nalmefene shows modest reductions in alcohol consumption, its overall clinical value must be carefully weighed due to high patient attrition rates in trials, meaning it is not the right choice for every patient.
When nalmefene is not the right starting point
Choosing the correct alcohol dependence treatment depends on the severity of a person's dependence, their withdrawal risk and personal treatment goals.
Nalmefene is not appropriate for individuals who:
Are experiencing physical withdrawal symptoms (such as shaking, sweating, or nausea when stopping).
Have a recent history of acute alcohol withdrawal.
Need or want to achieve immediate, total abstinence.
If you have a significant physical dependence on alcohol, stopping suddenly without medical supervision can be dangerous. These situations often require a dedicated in-patient or out-patient alcohol detox pathway rather than a reduction-focused medication.
How does nalmefene work to reduce alcohol consumption?
To understand how nalmefene helps reduce drinking, it is important to understand how alcohol affects the brain's reward system. While it shares some therapeutic goals with other treatments, a look at how naltrexone works shows that while both nalmefene and naltrexone target opioid receptors, they are distinct medications with different chemical profiles.
Nalmefene and the brain's opioid system
When alcohol is consumed, it interacts with reward and reinforcement pathways in the brain, including the endogenous opioid system. As detailed in the Selincro Summary of Product Characteristics (SmPC), nalmefene acts as an opioid system modulator. It exhibits antagonist activity at the mu (μ) and delta (δ) opioid receptors, and partial agonist activity at the kappa (κ) receptor.
By modulating these cortico-mesolimbic functions, nalmefene is thought to tone down the rewarding or reinforcing "buzz" that alcohol produces, thereby reducing the urge to keep drinking. A human laboratory study by Drobes et al. (2004) suggests that nalmefene successfully reduced alcohol-induced craving and stimulation in alcohol-dependent participants. A further exploratory double-blind study by Bach et al. (2021) showed that a single 18 mg dose reduced ventral-striatal alcohol cue reactivity and subjective craving.
Does nalmefene stop you getting drunk?
No. The Selincro SmPC states explicitly that taking nalmefene alongside alcohol does not prevent alcohol intoxication. It will not protect from impairment, slow reflexes, accidents, or the physical harms associated with heavy drinking. Nalmefene acts by altering the chemical reward or drive to continue consuming more alcohol once you start.
How is nalmefene taken?
Similar to disulfiram, nalmefene is administered on an "as-needed" dosing schedule rather than a fixed daily schedule, making it highly specific to an individual's drinking behavioural patterns.
The standard licensed dose is one 18 mg tablet. On days when perceived risk of drinking alcohol increases, it is recommended to take one tablet preferably 1 to 2 hours before the first drink.If alcohol consumption started without taking the medication, the SmPC advises taking one tablet as soon as possible. The maximum dose is one tablet daily, and the specific guidance tailored and provided by your prescriber should always be followed.
Why treatment starts with an assessment and drinking record
A competent clinician will request a full alcohol assessment before considering prescribing nalmefene. This clinical evaluation is essential for an overview of your current physical health, mental health, withdrawal risks, and any potential drug interactions. You will likely be requested to spend two weeks keeping an honest record of your daily alcohol intake to confirm that your drinking risk level remains high enough to warrant medical intervention.
Why nalmefene should be combined with psychosocial support
According to the Selincro patient leaflet and UK clinical guidance, nalmefene must never be treated as a standalone and definitive cure. It is licensed specifically to be used along with ongoing psychosocial support focused on treatment adherence and consumption reduction.
The foundation of The OAD Clinic's Controlled Drinking Programme is based on the ESENSE 1 clinical trial (Mann et al., 2013) and the ESENSE 2 clinical trial (Gual et al., 2013) which suggest 18 mg as an as-needed treatment regimen specifically alongside structured counselling. The outcome has been helping patients build long-term behavioural changes while using medication to manage the physiological drive or triggers.
How effective is nalmefene for reducing alcohol consumption?
The clinical data regarding nalmefene shows that it can be a valuable tool for a specific group of patients, though its effects are generally modest and results can vary depending on individual profile and circumstances.
What the clinical trials found
In the ESENSE 1 trial, patients taking nalmefene for a period of over six months showed reduction in heavy drinking days and total alcohol consumption compared to those taking a placebo. However, the data across trials is mixed. In the ESENSE 2 trial, while researchers observed a significant reduction in heavy drinking days at the six month baseline, the difference in total alcohol consumption across the full analysis group was not statistically significant. Nalmafene was found to yield favourable outcomes by month thirteen.
What systematic reviews say about the evidence
Independent reviews have pointed to a need to prove efficacy. The systematic review by Palpacuer et al. (2015) concluded that the overall clinical benefit of nalmefene was not firmly established, and advice that adherence to treatment was low due to side effects. More recently, the network meta-analysis by Chiang et al. (2024) confirmed that while nalmefene correlates with reductions in heavy drinking days over longer treatment timelines, patients experience significantly more side effects than those on a placebo. This confirms that nalmefene is not a one size fits all solution, but rather a medication suitable to a select number of patients who will not experience unpleasant side effects.
and who are undergoing counselling.
What are the side effects of nalmefene?
Like any medication that acts on the central nervous system, nalmefene carries a risk of side effects that should be medically discussed with an addictions specialist before starting treatment.
Common side effects
According to a pooled Phase III safety analysis by van den Brink et al. (2015), the most frequently reported adverse reactions include:
Nausea
Dizziness
Insomnia
Headache
In most clinical trials, these common reactions were rated as mild to moderate and typically occurred during the first few days of starting the medication. The Selincro SmPC also notes that less common psychiatric symptoms, such as confusion, hallucinations, or a feeling of detachment (dissociation) can occur and need immediate clinical attention.
Who should not take nalmefene?
Nalmefene is strictly contraindicated for individuals with severe liver or kidney disease, those experiencing recent acute alcohol withdrawal, and during pregnancy.
Also, because alcohol disorders and mental health problems frequently overlap, the SmPC advises clinical caution if a patient has an active psychiatric comorbidity, such as major depressive disorder. A comprehensive assessment is essential to address depression and alcohol use safely, as nalmefene itself is not a treatment for anxiety, depression or any other psychiatric condition.
Nalmefene and opioids, including painkillers, methadone and buprenorphine
Because nalmefene blocks opioid receptors, it must never be taken by anyone using opioid medication. This absolute contraindication includes:
Opioid-based prescription painkillers (such as codeine, tramadol, morphine, or oxycodone).
Opioid substitution therapies (such as methadone or buprenorphine).
Anyone with a current or recent opioid dependence or active opioid withdrawal symptoms.
If opioids and nalmefene are mixed, nalmefene will completely block the pain-relieving effects of opioid based medications and can trigger immediate, severe, and dangerous opioid withdrawal symptoms.
Final Thoughts
Nalmefene can be a highly effective, targeted option for selected adults in the UK who want to cut down on their alcohol intake rather than stop completely. It is not a solution for heavy drinking, it does not replace the need for therapeutic psychosocial support, and it requires strict compliance with safety rules regarding opioid medications. The most critical decision is determining whether a reduction goal is medically safe, or whether a structured detoxification and abstinence pathway is required.
If you want to reduce your drinking and are unsure whether nalmefene is appropriate, The OAD Clinic can assess your alcohol use, withdrawal risk, physical and mental health, and the treatment options that best fit your goals. You can contact The OAD Clinic directly to discuss our private, specialised alcohol treatment services in London and online.
Frequently Asked Questions
What is nalmefene used for?
Nalmefene is a prescription drug used to help some adults with alcohol dependence reduce alcohol consumption amounts. In the UK, it is intended for people who remain at a high drinking risk level after an initial assessment and detoxification, do not have physical withdrawal symptoms and do not need immediate detoxification. It should be used alongside ongoing psychosocial support.
How does nalmefene help reduce alcohol consumption?
Nalmefene acts on the brain's opioid system and is has been found to reduce some of the rewarding or reinforcing effects associated with alcohol. This may help reduce the urge to continue drinking or the amount consumed. The exact mechanism of action is not fully understood, and nalmefene is intended to support behavioural treatment rather than cure an alcohol use disorder.
Can you drink alcohol while taking nalmefene?
Nalmefene is specifically taken on days when there is a risk of drinking. However, nalmefene does not prevent intoxication or make alcohol safe. Its purpose is to help suitable patients reduce consumption as part of a treatment plan agreed with a qualified clinician.
How and when do you take nalmefene?
The licensed Selincro tablet contains 18 mg of nalmefene and is taken once daily as needed when there is a risk of drinking. It is preferably taken 1 to 2 hours before the anticipated time of drinking. If drinking has already started, the product information states the dose should be taken as soon as possible. Always follow your own prescriber's guidance and medicinal product leaflet.
What are the most common side effects of nalmefene?
The most commonly reported nalmefene side effects include nausea, dizziness, insomnia and headache. Many reactions in clinical trials were mild or moderate and happened around the start of treatment, but side effects can still affect whether the nalmefene is suitable or tolerable. Speak to your prescriber if symptoms are persistent, severe or concerning.
Can you take nalmefene with opioid painkillers, methadone or buprenorphine?
No. Nalmefene is contraindicated when combined with opioid medication, including opioid painkillers and opioid substitution treatment medication such as methadone and buprenorphine. It can block the effects of opioids and may precipitate withdrawal in opioid-dependents. You must always inform the prescriber about all opioid medication and any recent opioid use before starting nalmefene.
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Palpacuer C, Laviolle B, Boussageon R, Reymann JM, Bellissant E, Naudet F. Risks and Benefits of Nalmefene in the Treatment of Adult Alcohol Dependence: A Systematic Literature Review and Meta-Analysis of Published and Unpublished Double-Blind Randomized Controlled Trials. PLoS Med. 2015 Dec 22;12(12):e1001924. doi: 10.1371/journal.pmed.1001924. PMID: 26694529; PMCID: PMC4687857.
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Mann K, Bladström A, Torup L, Gual A, van den Brink W. Extending the treatment options in alcohol dependence: a randomized controlled study of as-needed nalmefene. Biol Psychiatry. 2013 Apr 15;73(8):706-13. doi: 10.1016/j.biopsych.2012.10.020. Epub 2012 Dec 11. PMID: 23237314.
Gual A, He Y, Torup L, van den Brink W, Mann K; ESENSE 2 Study Group. A randomised, double-blind, placebo-controlled, efficacy study of nalmefene, as-needed use, in patients with alcohol dependence. Eur Neuropsychopharmacol. 2013 Nov;23(11):1432-42. doi: 10.1016/j.euroneuro.2013.02.006. Epub 2013 Apr 3. PMID: 23562264.
