Selincro (Nalmefene) and Controlled Drinking

Selincro is the brand name for Nalmefene, a drug used to help control drinking. It is clinically effective for some kinds of alcohol-dependent drinkers. Prior to Selincro being released to the general public, alcohol dependency treatment has largely relied on abstinence programs (no drinking whatsoever). In North America, abstinence is an integral, and predominent, part of most alcohol dependence treatment programs.

In Europe however, abstinence is seen as one treatment avenue, but not the only one available. As more studies release their findings on controlled drinking, and medications to assist in this treatment, addiction specialists (particularly in North America) may be more apt to taking this approach for certain clients.

Selincro and Drug Substitution Therapy

Drug substitution therapy, also known as drug replacement therapy, involves a prescription medication to assist in the relief of withdrawal symptoms, a decrease in cravings or a loss of effects from the drug. Addictions involving opiates, opioids or amphetamines may be treated with drug substitution medication. Alcohol dependence can also be treated by drug substitution therapy, with nalmefene and naltrexone being the preferred medications.

Efficacy of Selincro

It has been widely accepted that alcohol causes the body to produce endorphins; naturally occurring chemicals in the body that produce feelings of pleasure within the reward system of the brain. The endorphins cause this sensation by acting on the brain's' opioid receptors. When taken, Selincro blocks these receptors; thereby, disrupting the reward system The end result for many users is a decreased urge to drink.

Produced by the Finnish company Lundbeck, and licensed in 2013 for use in the EU and UK, its effectiveness has been studied in clinical trials since 1994. Classified as an opioid receptor antagonist, it works within the brain's reward system -- a group of neural structures responsible for desire, craving, associative learning, pleasure, and positive emotions.

Selincro has been demonstrated to be successful in treating alcohol dependency, through what appears to be a dulling in the desire to drink. The exact brain mechanism of how it actually works on the brain has been unclear until recent research shed some light.

Selincro Brain Effects and Controlled Drinking

A recent study by Professor Lingford-Hughes, consulting psychiatrist and addiction expert in Imperial College Department of Medicine, shows some light on the subject.[^Lingford-Hughs] In this research, participants were all problem drinkers, and not seeking treatment at the time. They were asked to perform tests while being subjected to MRI scans and a single 18 milligram dose of Selincro, while a control group were given a placebo. The participants were also under the influence of alcohol during the testing, having received an intravenous infusion of 80 mg per 100 milliliters of blood.

To induce stimulation of the reward system, the participants were shown a screen with flashing symbols, some of which included small cash rewards. Snapshots were taken of the brain activity which highlighted the specific areas of stimulation. The scans revealed that when Selincro was taken with alcohol, activity in two areas of the brain, the dorsal and ventral striatum, was decreased.

Neuroscientists speculate these regions are linked to habit-formation abilities, as well as the brain's reward system. As one of the latest studies, it suggest Selincro blunts the response of habit forming areas in the brain in addition to interfering with the reward system.

> The findings indicate that the mechanism proposed to explain how the drug works is correct. Certainly this fits with my clinical experience, where people describe how being on these opiate blocking drugs means that they may start drinking, but then they just don't want any more - they don't crave it, they don't desire it, it doesn't taste nice or give them a good feeling.1

Selincro Prescribed for Moderate to Heavy Drinkers

Rather than advocating for abrupt abstinence, the objective of Selincro is to reduce alcohol consumption in patients who have a high risk of heavy drinking, but do not need detoxification. Selincro (Nalmefene) is generally prescribed to adults who consume at least 60 g of alcohol a day (for men) or at least 40 g of alcohol per day (for women).2 A 750ml bottle of wine, with a volume of 12%, contains around 70g of alcohol. Whereas a 330ml bottle of beer with a volume of 5% contains around 13g of alcohol. It should be used in conjunction with counselling and other therapeutic approaches, and is not suitable for people who need detoxification or are experiencing withdrawal. Pregnant women and patients with underlying health problems should consult a doctor before taking Selincro.

Selincro Use Patterns for Controlled Drinking

Prior to beginning Selincro treatment, the prospective patient's drinking patterns are reviewed. Over a two week period the patient records their alcohol consumption. This will be evaluated by the prescribing doctor to ensure Selincro is a good match. The medication is to be taken on days when the probability of drinking is high. For instance, if a person knows they will drink on the day of a sporting or social event, they will want to take the medication one to two hours beforehand. Selincro cannot be taken more than once a day.When forgotten, it should be taken as quickly as possible to receive benefits.

Varied adverse reactions are noted in an eMC study of 1,144 patients exposed to 18 mg Selincro tablets on an as-need basis.3 At least one in 10 users experienced insomnia, headache, nausea, and dizziness. Other side effects found to be prevalent in at least 1 in 100 users were malaise, dry mouth, muscle spasms and tremors. The majority of these reactions were mild to moderate, and of short duration. Researchers believed them to be in relation with the initiation of treatment.

Further Research Studies in Selincro Effectiveness

At least three clinical trials for Selincro have been conducted. In a supervised one year study, nalmefene was notably effective in adults who were considered to be at risk drinkers. Patients treated with the medication showed a 60 percent reduction in alcohol consumption after 6 months of taking it. Notes from these studies include:

  • Selincro is more effective than the placebo in its ability to reduce alcohol consumption,
  • Selincro oes not reach its full capacity in the brain for upwards of two months or more, and
  • Effects are noticeable within the first four weeks

After 6 months of use, the number of heavy drinking days in any given month was reduced from 23 days to 10. 2 Daily alcohol consumption fell from an average of 102 g to 44 g. Participants in the study were also actively participating in psychosocial intervention specifically focusing on motivation and commitment.

Other Medications Used to Treat Alcohol Dependency

Up until recently, approved medications for the treatment of alcohol dependence 4 have been indicated to be an aid in the management of abstinence. None was for the reduction in consumption. Available through oral tablets or long release injectables, these have been approved by agencies including the FDA, EMA and TGA. Three common medications used as a drug substitution to treat alcohol dependency include:

  • Naltrexone - As an opioid receptor antagonist, it works by blocking μopioid receptors in the brain. This in turn blocks the effects of alcohol and reduces the urge to drink. Over time it can lead to fewer cravings and a decrease in the desire to drink. Naltrexone, also known as ReVia, is also used to treat opiate dependencies.
  • Disulfiram - More commonly known as Antabuse, disulfiram supports the treatment of alcohol dependency by producing an acute sensitivity to alcohol. If a person is taking the oral medication and then drinks, he or she may feel hangover like effects such as a throbbing headache, nausea, vomiting, thirst and confusion. Disulfiram is being studied for its ability to treat cocaine dependence by preventing the breakdown of dopamine, a neurotransmitter stimulated by the drug.
  • Acamprosate - Although the exact mechanism of action is unknown, acamprosate, or Campral, targets various channels in the brain which results in decreased alcohol cravings. This type of treatment typically works best alongside cognitive behavioural therapy and social support.

In addition to these prescriptions, vitamins and mineral supplements may also be used. Each medication has been studied for its effectiveness and has produced repetitive successful results. What is also inherently conclusive is that they are specifically meant to be taken when abstinence is a goal. Selincro is an alternative to these medicines and can be used when abstinence is not an option.

Selincro is Effective under Specific Conditions

Selincro treatment is suited to certain kinds of alcohol-dependent drinkers. Very heavy or long-term dependent drinkers are at high risk for physical withdrawal, and for this group Selincro is not advised. When this is a possibility, alcohol detoxification is highly recommended to avoid a potentially fatal onset of symptoms. The medication is not intended to be a replacement for another medication; nor is it meant to eliminate a final goal of abstinence. Rather it is a type of drug substitution therapy aimed to help decrease alcohol consumption in heavy drinkers. People with a strong opiate dependency such as heroin or morphine, or those experiencing an opioid withdrawal should also not take Selincro. Doing so could result in adverse reactions that require immediate medical attention.