Naltrexone is an FDA approved medication for alcohol use disorder (AUD) as well as opioid use disorder (OUD). Find out more about how it works, how it is taken and whether or not it might be useful for you.
Medications & Alcohol Recovery
Fewer than 4% of people with alcohol use disorder (AUD) are prescribed medications that are approved by the U.S. Food and Drug Administration to treat their disorder. Those that do get medications these days most often get Naltrexone, but there are two other medications - acamprosate and disulfiram - that are used to treat alcohol use disorder.
What is Naltrexone?
Naltrexone is an FDA approved pill that is taken for two indications: to prevent use of alcohol or to prevent use of opioids. It is an opioid antagonist, which will be explained more below. Naltrexone is the formulation of the opioid antagonist that is slower acting in the body, as compared to Naloxone which is also a fast acting opioid antagonist used to reverse an opioid overdose in an acute situation.
There have been many Meta-analyses of clinical trials for alcohol dependence showing a reduction in alcohol consumption in patients on Naltrexone compared to placebo 
How Does Naltrexone Work in the Body?
Naltrexone is not an opioid, and it is not addictive. Naltrexone is actually an opioid antagonist, meaning that it binds to opioid receptors and turn them off instead of turning them on the way an opioid agonist does. In this way, it blocks up the opioid receptors and prevents someone from using an opioid to “get high”. This is the way it prevents opioid misuse for people with OUD.
The way it works to prevent alcohol misuse, however, is less clear. There is some thought that naltrexone also binds to some of the same receptors as alcohol does, but it is not known for sure. Regardless of the exact physiological mechanism by which it works, naltrexone has consistently shown to decrease cravings in individuals with AUD.
How is Naltrexone Administered?
Naltrexone comes in pill form or injectable form. The pill is usually dosed at 50 mg daily although occasionally patients require up to 100 mg daily to prevent cravings.
Usually doctors recommend that a patient start by taking the pills for a few days to ensure that they are well tolerated. After that, they can either continue to take a pill every day or switch to an injectable medication (Brand name “Vivitrol”) that they receive once a month. Some people prefer an injection because it does not require remembering to take a pill daily. However, either the pill (if taken daily) or the injection seem to work equally well to prevent alcohol use.
What are the side effects of Naltrexone?
Naltrexone has few side effects or adverse effects and is generally very well tolerated and safe. Occasionally patients will report nausea, headache, dizziness, or fatigue. More severe adverse effects include liver damage, but this is very rare and was found usually in the setting of people using doses more than as prescribed.
In conclusion, Naltrexone is an overall safe and effective treatment for AUD and can help reduce the amount an individual is drinking, leading to overall health benefits. Talk to your doctor if you think Naltrexone might be a good treatment for you.