How Long Does Naltrexone Block Alcohol Cravings?

As a physician on the Monument platform, I’ve seen many of my patients benefit from medication to help stop drinking. I’m often asked about what naltrexone is, how it works, and the duration of naltrexone’s effectiveness. Let’s dive in. 

What is Naltrexone?

Naltrexone is an FDA-approved medication proven to help people cut back or stop drinking. It works to reduce the pleasurable effects of drinking alcohol and decrease alcohol cravings. This allows for more brain space and energy for making other lifestyle changes that support sobriety or moderation. 

How Long Does Naltrexone Block Alcohol Cravings on Average?

Cravings are influenced by several mental, social, and health factors, and therefore each individual’s experience is unique. That said, most people report experiencing anti-craving effects for approximately 24 hours after they take their dose of naltrexone medication. This is why physicians like myself prescribe naltrexone to be taken daily at the same time each day for most patients. This is also aligned with the FDA’s prescribing information.

What Causes Alcohol Cravings?

Learning the science behind alcohol cravings can help to understand the benefits of naltrexone. When you drink alcohol, endorphins bind to opioid receptors in the brain and trigger the release of dopamine (AKA our “feel-good hormone”) in the brain, producing a short-term sense of euphoria. Over an extended period of heavy drinking, the brain learns to associate alcohol with these positive feelings, and even just the thought of drinking can increase dopamine in the brain. This anticipation is what causes alcohol cravings. Then, when you consume alcohol, even more dopamine is released. This ramp up of dopamine can lead to even more alcohol consumption than initially intended, including heavy drinking or binge drinking.

How Does Naltrexone Work?

Naltrexone medication works by blocking the brain’s endorphin receptors, indirectly limiting the release of dopamine after alcohol consumption. This can help individuals cut back on drinking because it makes drinking less pleasurable. When drinking on naltrexone, it’s less likely that dopamine levels will ramp up and that you’ll continue drinking to excess once you’ve started. As you take naltrexone over time, the brain’s association between alcohol and pleasure weakens, which allows alcohol cravings to subside. You don’t have to commit to abstinence in order to begin naltrexone treatment.

Naltrexone Effectiveness

Multiple clinical trials and studies have demonstrated the effectiveness of naltrexone. A meta-analysis published in The Journal of the American Medical Association in 2014 showed that naltrexone reduces the risk of returning to both drinking as well as heavy drinking.¹ Another meta-analysis showed that naltrexone reduced the likelihood of relapse by 38%.² 

For some people, naltrexone can immediately help change their relationship with alcohol. Others find that naltrexone treatment works best in conjunction with other forms of support, such as cognitive behavioral therapy. It’s important to note that naltrexone is not a “miracle drug” in itself, and is most effective in combination with other treatment modalities. 

woman exiting coffee shop

How Long Does Naltrexone Stay in Your System?

It can take about 22 hours for naltrexone to leave your system entirely. However, naltrexone also gets metabolized by the liver to become 6-ß-naltrexol, an active metabolite that can have the same effect as naltrexone. This can prolong some of the effects of naltrexone for up to 70 hours. However, it’s still recommended to take this medication daily to yield the best health outcomes.

How Long Does it Take for Naltrexone to Work?

A naltrexone pill becomes active in your system approximately one hour after taking it. Some people find it effective to take their daily naltrexone dose approximately one hour before they would typically have an alcoholic drink.

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Drinking While on Naltrexone

Is it Safe to Drink While Using Naltrexone?

There is no risk of a dangerous reaction between naltrexone and alcohol. However, naltrexone only blocks the pleasurable effects of alcohol, not the physical side effects. Drinking on naltrexone doesn’t prevent the risks associated with the effects of intoxication, including impaired judgment, slowed thinking, and worsened motor skills.

Can You Still Get Drunk While Using Naltrexone?

You still experience the physical experience of intoxication while taking naltrexone. However, naltrexone minimizes the pleasurable effects associated with drinking. This can make it more difficult to recognize your level of intoxication while drinking on naltrexone.  

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Individual Factors That Impact How Naltrexone Works in Your Body

Just like any medication, each individual’s biological and physiological background can play a role in its effectiveness. There are several known factors that can influence how you might respond if you take naltrexone, which you can discuss further with your doctor. 


Genetics can play a role in the likelihood of developing alcohol use disorder (AUD), and help in the effectiveness of naltrexone itself. There’s research to suggest that people with family members who meet the criteria for or have recovered from AUD may respond better to naltrexone treatment.¹ Genetic research also suggest that people with a particular type of opioid receptors (Asn40Asp polymorphism) may also have better outcomes if they take naltrexone.² These may be factors to consider when deciding which medication to stop drinking is right for you.

Drinking For ‘Reward’ Vs ‘Relief’

Your current relationship with alcohol can also have an impact. Some studies suggest that naltrexone works better for people who drink alcohol for the rewarding effects of alcohol, rather than to alleviate the adverse side effects of alcohol withdrawal.3 While naltrexone blocks the rewarding feelings that can come from drinking, it doesn’t prevent or relieve the physical side effects of unhealthy alcohol use. If you experience alcohol withdrawal symptoms, it’s crucial to connect with a medical health professional. After making a plan to stop drinking safely, medication may still be a helpful tool in your journey and longer-term alcohol recovery timeline.

If you believe you are experiencing alcohol withdrawal syndrome, please contact your health provider immediately and visit to find a location to get supervised detox near you. If this is a medical emergency, call 911.


The recommended dose for most patients is a 50 mg daily oral naltrexone pill. However, you  should speak to your healthcare provider about what dosage is right for you to take. Some people may need to take a higher dose to feel the effects of naltrexone. Alternatively, others adjust their dosage in order to avoid side effects. Although naltrexone is generally well-tolerated, some side effects like headaches and nausea can occur for some individuals. Your physician can adjust your dosage in order to minimize side effects. 

You might also want to discuss the time which you take your medication with your provider. Some people find that taking their daily dose one hour before they would typically drink or experience cravings works best, while others don’t notice any difference in therapeutic effect throughout the day. Your physician will help you find the right dosage, manage side effects, and determine the best time to take the medication based on your experience and health needs. You can also discuss daily dosing, which is standard at Monument, vs. The Sinclair Method.

Building a Treatment Toolkit

While naltrexone can be a helpful tool on your journey, it’s not a miracle drug on its own. Alcohol affects all dimensions of our health and wellness, therefore changing your relationship with alcohol is not only a physical experience, but often involves mental health and social support as well. That’s why the positive effects of naltrexone are amplified when combined with other treatment options such as specialized alcohol therapy and alcohol support groups. Therapy can help you develop healthier coping mechanisms, address co-occuring mental health conditions, and make progress towards your goals. Therapist-moderated support groups can help provide peer encouragement and accountability throughout your journey with moderation or abstinence.

Other Frequently Asked Questions About Naltrexone

Naltrexone Side Effects

While naltrexone is typically well-tolerated, there are some possible side effects. Nausea and headache are the most common. Your physician can adjust your treatment plan in order to minimize any potential side effects.

Drug Interactions with Naltrexone

There aren’t many dangerous drug interactions associated with naltrexone. The most common medications that can pose a risk are opioid-containing medicines for pain, diarrhea, colds, and cough. It’s vital you share all of your health history and current medications with your provider before taking naltrexone.

Is Naltrexone Addictive?

According to SAMHSA, naltrexone is not addictive, and there are no withdrawal symptoms associated with the discontinuation of taking naltrexone.

Cutting back on alcohol can have a tremendous impact on your health and happiness. As a doctor on the Monument platform, I’ve been able to witness how powerful a tool naltrexone medication can be for curbing cravings and freeing up the energy and brain space for patients to work on other parts of their recovery. Everyone’s experience is different, and the more resources you have in your toolkit, the greater your chances of success. You can do this, and speaking to a physician about naltrexone is a great next step to take.


  1. Addiction. Efficacy and safety of naltrexone and acamprosate in the treatment of alcohol dependence: a systematic review,” Accessed March. 11, 2022. 
  2. Biol Psychiatry. “Family history of alcoholism influences naltrexone-induced reduction in alcohol drinking,” Accessed March. 11, 2022. 
  3. Neuropsychopharmacology. “A Functional Polymorphism of the μ-Opioid Receptor Gene is Associated with Naltrexone Response in Alcohol-Dependent Patients,” Accessed March. 11, 2022. 
  4. Neuropsychopharmacology. “Precision Medicine in Alcohol Dependence: A Controlled Trial Testing Pharmacotherapy Response Among Reward and Relief Drinking Phenotypes,” Accessed March. 11, 2022. 
  5. Eur Arch Psychiatry Clin Neurosci. FMRI-based prediction of naltrexone response in alcohol use disorder: a replication study,” Accessed March. 11, 2022. 

Naltrexone has the capacity to cause hepatocellular injury (liver injury) when given in excessive doses. Naltrexone is contraindicated in acute hepatitis or liver failure, and its use in patients with active liver disease must be carefully considered in light of its hepatotoxic effects. In the treatment of alcohol dependence, adverse reactions include difficulty sleeping, anxiety, nervousness, abdominal pain/cramps, nausea and/or vomiting, low energy, joint and muscle pain, headache, dizziness and somnolence. This is not a complete list of potential adverse events associated with naltrexone hydrochloride. Please see Full Prescribing Information for a complete list.

Disclaimer: Our articles and resources do not constitute clinical or licensed therapy or other health care services. If you need counseling or therapy services please contact a licensed provider. If this is a medical emergency, call 911.

About the Author

Avatar photoMonument is an online platform for those looking to change their relationship with alcohol. We connect members to a free anonymous community, therapist-moderated groups, and a collection of resources to provide the support and information they deserve. Members seeking medical treatment are introduced to a licensed physician and a specialized therapist to develop a personalized treatment plan specific to their goals. Monument is affordable, accessible, and research-based, so a healthy relationship with alcohol is attainable and celebrated by all.