Key Takeaways
- Naltrexone is an FDA-approved medication for alcohol use disorder that reduces the urge to drink and the reward of drinking — with strong evidence from multiple randomized clinical trials.
- Despite proven effectiveness, only about 8% of people with alcohol use disorder receive any medication — naltrexone remains severely underutilized.
- Naltrexone works by blocking opioid receptors, which are involved in the rewarding effects of alcohol. It blunts the euphoria of drinking, making alcohol less appealing over time.
- Vivitrol, a once-monthly injectable form of naltrexone, eliminates the need for daily pills and significantly improves medication adherence.
- Naltrexone is most effective when combined with behavioral therapy — particularly the Sinclair Method (targeted naltrexone) and cognitive behavioral therapy.
In This Article
What Is Naltrexone?
Naltrexone is an opioid antagonist — a medication that blocks opioid receptors in the brain without producing any opioid effects itself. It was originally developed and FDA-approved for opioid use disorder in 1984, and received FDA approval for alcohol use disorder (AUD) in 1994. It is available as a daily oral tablet (ReVia, generic naltrexone) and as a once-monthly injectable formulation (Vivitrol).
According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), naltrexone is one of three FDA-approved medications for alcohol use disorder — alongside acamprosate and disulfiram — and has among the strongest evidence bases of the three for reducing heavy drinking days. Despite this, it remains dramatically underused: SAMHSA data consistently shows that fewer than 10% of people with AUD receive any pharmacotherapy.
How Naltrexone Works for Alcohol
Alcohol produces many of its rewarding effects — including euphoria, relaxation, and stress reduction — by indirectly stimulating the brain's opioid system. When alcohol is consumed, it triggers the release of endorphins that bind to opioid receptors in the reward circuitry. This opioid activity is a major driver of the pleasurable "buzz" of alcohol and the craving to drink more.
Naltrexone blocks mu-opioid receptors, preventing endorphins released by alcohol consumption from binding to them. The result: drinking produces less euphoria, less of a "buzz," and less reinforcement of the urge to keep drinking. Over time, this pharmacological "extinction" of the alcohol reward reduces cravings and makes it easier to cut down or stop.
Naltrexone Does Not Make You Sick When You Drink
This is a critical point of confusion. Naltrexone is NOT disulfiram (Antabuse), which causes nausea and vomiting if alcohol is consumed. Naltrexone simply reduces the reward of drinking — it has no aversive reaction to alcohol. This makes it safer and often more acceptable to patients who are not yet fully committed to abstinence.
What the Research Says
Naltrexone has been studied in over 50 randomized controlled trials and multiple systematic reviews. The evidence consistently shows clinically meaningful benefits:
- A landmark Cochrane systematic review of 50 RCTs found naltrexone significantly reduced the rate of return to heavy drinking (relative risk 0.83) and the number of drinking days per month compared to placebo.
- The COMBINE Study (JAMA, 2006) — the largest AUD medication trial in history with 1,383 participants — found that naltrexone combined with medical management produced significantly better outcomes than placebo on the primary drinking outcome measures.
- The injectable Vivitrol formulation showed particularly strong results in a pivotal trial published in Archives of General Psychiatry, with a 25% reduction in heavy drinking days compared to placebo, and even stronger results in patients who abstained in the week before starting treatment.
- A 2014 meta-analysis in JAMA Psychiatry found naltrexone produced a number needed to treat (NNT) of about 12 to prevent one person from returning to heavy drinking — comparable to the NNT of many widely-accepted medical treatments.
Oral Naltrexone vs. Vivitrol (Injectable)
| Feature | Oral Naltrexone (ReVia) | Injectable Naltrexone (Vivitrol) |
|---|---|---|
| Dose | 50mg tablet, once daily | 380mg injection, once monthly |
| Adherence | Requires daily pill-taking; easy to skip | Once-monthly; eliminates daily adherence problem |
| Cost | Lower — generics widely available | Higher — but often covered by insurance |
| Best for | Motivated patients with good daily routine | Patients with adherence challenges or severe AUD |
| Flexibility | Can stop any day; Sinclair Method-compatible | Less flexible — 28-day commitment per injection |
The Sinclair Method
The Sinclair Method (TSM) is a specific protocol for naltrexone use developed by Finnish researcher David Sinclair, PhD. Rather than requiring abstinence before and during treatment, TSM instructs patients to take naltrexone one hour before every drinking occasion — and to allow themselves to drink as usual after taking the medication.
The theory: by repeatedly experiencing drinking without the opioid-mediated reward, the brain gradually "unlearns" the association between alcohol and pleasure through pharmacological extinction. Over months, most patients find their craving for alcohol decreasing naturally, and many achieve significant reduction or abstinence without being forced into immediate abstinence.
TSM Research Results
A Finnish study of TSM published in Alcohol and Alcoholism found that 78% of patients achieved either controlled drinking or complete abstinence after 3 years of TSM use. The Sinclair Method is particularly appealing to patients who are not ready to commit to immediate abstinence, as it works with drinking rather than against it — at least initially.
Who Benefits Most from Naltrexone
Research has identified several patient characteristics associated with stronger responses to naltrexone:
- Family history of alcoholism: Patients with a positive family history of AUD show larger reductions in alcohol craving and consumption on naltrexone — possibly reflecting genetic differences in opioid receptor density or function.
- High craving: Patients who report intense cravings for alcohol tend to respond better to naltrexone than those whose drinking is more habitual and less craving-driven.
- OPRM1 gene variant (A118G): Research suggests that patients carrying the Asn40Asp variant of the mu-opioid receptor gene (OPRM1) may respond more strongly to naltrexone. Pharmacogenomic testing is available but not yet standard of care.
- Early abstinence before starting: Patients who achieve even a brief period of abstinence before starting injectable Vivitrol tend to have better outcomes.
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Side Effects & Precautions
Naltrexone is generally well-tolerated, with most side effects mild and transient:
- Common: Nausea (most common, especially in first week), headache, fatigue, anxiety, insomnia, decreased appetite
- Injection site reactions (Vivitrol): Pain, tenderness, swelling at the injection site — occasionally severe with tissue necrosis in rare cases
- Mood effects: Some patients report dysphoria or "emotional blunting" — particularly relevant for patients with co-occurring depression
Critical precautions:
- Liver toxicity: Naltrexone can cause dose-dependent liver damage at very high doses. Liver function tests should be checked before starting and periodically during treatment. Naltrexone is contraindicated in acute hepatitis or liver failure.
- Opioid use: Naltrexone is absolutely contraindicated in patients who are physically dependent on opioids — it will immediately precipitate severe withdrawal. Patients must be opioid-free for 7–10 days before starting naltrexone (longer for methadone). Always perform a naloxone challenge test before initiating in patients with recent opioid use.
- Pain management: Naltrexone blocks opioid analgesia. Patients on naltrexone needing surgery or pain management must inform their medical team.
Naltrexone vs. Other FDA-Approved AUD Medications
| Medication | How It Works | Best For | Key Limitation |
|---|---|---|---|
| Naltrexone | Blocks opioid reward of alcohol | Reducing heavy drinking; patients with cravings | Contraindicated with opioid use |
| Acamprosate | Reduces glutamate-driven craving after abstinence | Patients committed to abstinence; post-detox | Must be abstinent; less effective for active drinkers |
| Disulfiram (Antabuse) | Causes aversive reaction when alcohol consumed | Highly motivated, externally monitored patients | Dangerous cardiac/respiratory reactions if alcohol consumed; compliance issues |
How to Get Started on Naltrexone
Naltrexone is available by prescription from any licensed physician, including primary care physicians, psychiatrists, and addiction medicine specialists. It does not require a special license to prescribe (unlike buprenorphine for opioid use disorder). Here are the steps:
- Medical evaluation: Your provider will review your medical history, check liver function tests, and screen for opioid use to confirm naltrexone is safe for you.
- Insurance verification: Most insurance plans cover oral naltrexone. Vivitrol requires prior authorization from most insurers but is usually covered. Our specialists can verify your benefits at no cost.
- Treatment program: Naltrexone is most effective when combined with counseling. MAT programs, outpatient treatment, and IOP all incorporate naltrexone as part of comprehensive AUD treatment.
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Frequently Asked Questions
Sources
- NIAAA. (2023). Treatment of Alcohol Problems: Finding and Getting Help. niaaa.nih.gov
- Anton RF, et al. (2006). Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE). JAMA, 295(17), 2003–2017.
- Rösner S, et al. (2010). Opioid antagonists for alcohol dependence. Cochrane Database of Systematic Reviews.
- Garbutt JC, et al. (2005). Efficacy and tolerability of long-acting injectable naltrexone for alcohol dependence. JAMA, 293(13), 1617–1625.
- SAMHSA. (2023). Medication for the Treatment of Alcohol Use Disorder. samhsa.gov
- ASAM. (2023). National Practice Guideline for the Treatment of Opioid Use Disorder. asam.org
Dr. James Whitfield, MD
Dr. Whitfield is a board-certified addiction medicine physician with over 15 years of experience treating substance use disorders and co-occurring psychiatric conditions. He completed his fellowship at Johns Hopkins University School of Medicine and serves as a clinical advisor for addiction treatment facilities across the southeastern United States.