Naltrexone is an opioid antagonist which has been approved by the FDA for the treatment of Alcohol Dependence since 1994. An opioid antagonist is a drug which blocks the opioid receptors in the brain and prevents opioids from binding to them. An antagonist not only produces no high, it prevents people from getting any high from drugs like heroin since it prevents them from binding to the receptors in the brain. Naltrexone also prevents the endorphins, the brain's natural painkillers, from binding to the receptors in the brain. One well-known opioid antagonist is Narcan (naloxone); a shot of Narcan can reverse a heroin overdose and bring a person back to life by knocking all the heroin molecules off the receptors in the person's brain. It also puts the person into instant withdrawal. Naltrexone comes in pill form and is taken orally, although it is also available in the form of a 30 day implant known as Vivitrol.
The normal way of prescribing naltrexone for the treatment of Alcohol Dependence in the US is to tell people to abstain from alcohol and to take naltrexone daily. A VA study of 627 subjects who were prescribed naltrexone in this manner, however, found no significant difference between those who received the medication and those receiving placebo. The COMBINE Study looked at 1,383 subjects and found significant differences between subjects receiving naltrexone and those receiving placebo, but the effect size was very small. For example, subjects receiving naltrexone without CBI (cognitive behavioral intervention) had an average of 80.6% days abstinent whereas those receiving placebo without CBI had an average of 75.1 days for an effect size of 0.22.
By way of contrast, Dr. David Sinclair in Finland claims an 80% cure rate for Alcohol Dependence when naltrexone is prescribed according to The Sinclair Method. Dr. Sinclair's research has been published in the peer reviewed journals Alcohol and Alcoholism and the Journal of Clinical Psychopharmacology. The Sinclair Method has been adopted as a standard treatment protocol for Alcohol Dependence in Finland.
With The Sinclair Method, people only take naltrexone before drinking and never otherwise. Naltrexone is not like antabuse - it causes no sickness when taken with alcohol and there is no noticeable change in people's drinking behavior when they first start taking naltrexone; this change in behavior only appears over time. With The Sinclair Method Naltrexone is taken one hour before drinking alcohol; the usual dosage is 50 mg although this may need some adjustment up or down to fit the individual. This results in a process called the pharmacological extinction of Alcohol Dependence. At the end of four to six months of treatment with The Sinclair Method, 80% of Alcohol Dependent subjects are either drinking moderately or abstaining from alcohol.
Pharmacological extinction works on the premise that Alcohol Dependence is a form of Pavlovian conditioning. When people drink alcohol, endorphins are released into the brain, and this reinforces the behavior of drinking alcohol. Naltrexone blocks these endorphins from binding to the brain's receptors and the alcohol drinking behavior is extinguished. Much like when Pavlov's dogs were presented with food when a bell was rung, these dogs became conditioned to salivate at the sound of the bell alone. However, when these dogs continued to be presented with the stimulus of the ringing bell in the absence of food, the behavior of salivating at the sound of the bell soon became extinguished.
When Dr. Sinclair, in an open label trial, compared those who were told to abstain and take naltrexone daily with those who were told to take naltrexone only before drinking, he found that there was no significant benefit for the naltrexone group over the placebo group for the subjects who were told to abstain and take the medication daily. However, for subjects who were told to take the medication only before drinking there was a highly significant benefit of naltrexone over placebo (P = 0.008) in terms of relapse to heavy drinking. Moreover, the Sinclair Method group who received naltrexone did significantly better than the daily naltrexone group on this measure as well (P = 0.041). Giving alcoholics naltrexone daily and telling them to abstain from drinking is not effective. Giving alcoholics naltrexone and telling them to take it only before drinking alcohol is highly effective and cures Alcohol Dependence.
Although naltrexone is effective at reducing cravings for alcohol, it has not yet been established that this anti-craving effect shows up in those who abstain from alcohol, or if it is only present in those who drink on the naltrexone. Although some people who are abstaining report reduction in craving, this could be a placebo effect.
It remains difficult to understand why so few American physicians, therapists, and addiction counselors are familiar with The Sinclair Method. A very detailed description of The Sinclair Method written for the layman can be found in Dr. Roy Eskapa's book, The Cure for Alcoholism: The Medically Proven Way to Eliminate Alcohol Addiction.