Does Naltrexone Work?

Naltrexone moves heavy drinking most

Pooled results are often given as a number needed to treat (NNT): how many people need the drug instead of a placebo for 1 more to benefit. A 2023 review of 118 trials of alcohol medicines, done for the Agency for Healthcare Research and Quality (AHRQ), found these NNTs for 50 mg naltrexone tablets¹:

• Return to heavy drinking: NNT 11 (95% confidence interval, 5 to 41).
• Return to any drinking: NNT 18 (95% confidence interval, 4 to 32).

Both intervals are wide, so the real effect may be noticeably larger or smaller than the headline number.

The 2010 Cochrane review of 50 trials and 7,793 people found the risk of heavy drinking 17% lower and drinking days about 4% fewer. Its 4% lower risk of any drinking was not statistically significant.⁴ Comparisons with other alcohol medicines are in pooled results on the AUD page.

Success rates ranged from no benefit to relapse more than halved

Trials measured different outcomes in different people, so the naltrexone success rate depends on the trial. Five trials show the range:

The Sinclair Method's 78% figure comes from an uncontrolled clinic program, not a trial: see where the 78% comes from.¹⁴

Pill-taking explains part of the gap between trials

In a 97-person trial, naltrexone's effect across everyone was modest. It was larger, on several outcomes, in people who finished treatment and took their pills.¹⁵ A compliance analysis of a 160-person trial found the benefit of naltrexone combined with cognitive behavioral therapy roughly doubled in size (an effect size of about 0.2, rising to about 0.4 to 0.5) when limited to people who took their medicine.¹⁶ These subgroups were not randomized, and in the second trial, age predicted who took the pills.¹⁶

The VA trial offered every participant a program to improve pill-taking and still found no difference.⁵ A 2007 reanalysis of that trial and a second negative trial, in women, sorted people by their day-to-day drinking pattern. Naltrexone doubled the odds of following an "abstainer" pattern rather than a "consistent drinker" one, with no significant effect on abstainer versus occasional-drinker patterns.¹⁷ It reanalyzed the same two trials and added no new participants.

Nor can anyone yet pick likely responders in advance: family history and a gene variant have been studied without a clear answer (no test predicts who it will help).^7,8

When it works, craving and the pace of drinking drop

Naltrexone blocks opioid receptors in the brain involved in the reward from drinking.¹⁸ It is not aversive: drinking on it does not cause a disulfiram-like sickness reaction.¹⁹

In a laboratory study, 18 people with alcohol dependence who were not seeking treatment took naltrexone or placebo for 6 days, then had a starter drink and the chance to order up to 8 more. Both groups responded alike to the first drink. After it, people on naltrexone drank fewer drinks, more slowly, and reported less craving.²⁰

In the 1992 Volpicelli trial, the difference showed up after a slip. Of the people who drank at all during treatment, 19 of 20 on placebo went on to relapse, against 8 of 16 on naltrexone.⁶ How soon these effects begin is covered in how long does naltrexone take to work?

You can start the tablets while still drinking

Naltrexone tablets can be started while someone is still drinking.¹⁸ The APA recommendation covers people aiming to cut down as well as people aiming to stop.²¹

The shot is different. In its main trial, heavy drinking days fell overall. Its extra gains on drinking days and abstinence were confined to the small group (8%) who had gone a week without alcohol before the first shot. For the other 92%, the label says those effects "were not evident."²² What a drink feels like on naltrexone is covered in drinking on naltrexone.

Naltrexone not working? Five things to check

1. Are you taking it every day? Trial participants who took their pills did better (see above).¹⁵
2. Has it been long enough? NICE, writing for people who start after assisted withdrawal, says to stop if drinking persists 4 to 6 weeks in; the VA/DoD guideline gives 3 months at 50 mg a day.^9,10 Early timing is on how long does naltrexone take to work?
3. Is there support around it? The tablet label says it has not been shown to help except as part of a wider treatment program.¹⁹ The support can be light: in COMBINE, adding an intensive behavioral therapy did not beat naltrexone with brief medical check-ins.¹³
4. What dose are you on? The label dose is 50 mg a day; COMBINE used 100 mg, twice the label dose.^13,19 A SAMHSA advisory lists raising the dose among general options after a relapse on any alcohol medicine, without naming a naltrexone dose. The tablet label notes a possibly higher risk of liver injury with single doses above 50 mg.^19,23 Don't change the dose on your own.
5. Would another medicine fit better? If one alcohol medicine doesn't help, trying another is often worthwhile.¹⁸ The VA/DoD guideline rates topiramate (off-label in the US) in the same top tier as naltrexone, with acamprosate and disulfiram one tier lower.¹⁰ See how naltrexone compares with other medicines to stop drinking, or compare naltrexone vs acamprosate, the monthly Vivitrol shot and naltrexone vs disulfiram.

For opioids, the shot has stronger evidence than the daily pill

A 2011 Cochrane review of 13 trials with 1,158 people found oral naltrexone no better than placebo or no medicine on its main outcomes, and only 28% of participants stayed in treatment. In trials where taking the pill was enforced, it did better on retention and abstinence (risk ratio 2.93).²

The monthly shot has stronger trials. In a 24-week trial of 250 adults in Russia after detox, people on Vivitrol had confirmed opioid-free results in a median 90% of weeks, against 35% on placebo.³ In the X:BOT trial of 570 US adults, fewer people managed to start Vivitrol than Suboxone (72% vs 94%), and among those who did start, relapse rates were similar.²⁴ For opioid use disorder, the VA/DoD guideline recommends buprenorphine or methadone and only suggests the shot.¹⁰ Starting rules and overdose records for the shot and Suboxone are compared on naltrexone vs Suboxone.

Once naltrexone wears off, an opioid dose a person used to tolerate can kill: see the overdose warning.¹⁹ Naltrexone is a different drug from naloxone (Narcan); see naltrexone vs naloxone.

Only 2.5% of people with alcohol use disorder get medication

In 2024, 2.5% of people in the US aged 12 and older with alcohol use disorder (about 697,000 of an estimated 28.0 million) received medication for it.^25,26 Both US guidelines put naltrexone in their top tier: grade 1B from the APA and "Strong for" from the VA/DoD.^10,21

Prescribing it needs no special training or license, according to NIAAA, which also calls the approved alcohol medicines non-addictive and says misinformation makes some patients hesitate.¹⁸ FDA removed the boxed liver warning from the ReVia tablet label in October 2013; the current tablet label still warns about liver injury.^19,27

Weight loss and low-dose naltrexone are separate questions

Naltrexone tablets are approved for alcohol dependence and for blocking the effects of opioids, not for weight loss.¹⁹ Contrave, which combines naltrexone with bupropion, is approved alongside diet and exercise for weight management in some adults with obesity or overweight.²⁸ Low-dose naltrexone (LDN) is an off-label use with separate evidence, covered on low-dose naltrexone.

Share your experience

Did naltrexone help you, or not? Tell us how it went, including if it didn't work, or read other people's naltrexone reviews.

How we checked

• Sources include trial abstracts, the 2023 AHRQ review, Cochrane reviews (2010, 2011), current labels, the APA, VA/DoD and NICE guidelines, and NIAAA's 2024 treatment figures.^{1,2,4,9,10,19,21,22,26}
• The trial table counts 5 trials; two reanalyses are not counted again.
• Relapse figures, AHRQ NNTs with their 95% confidence intervals, Cochrane risk figures and the Garbutt and COMBINE outcomes were checked against saved copies on October 17, 2026.

Programs that prescribe naltrexone

Online programs that prescribe naltrexone for alcohol, with their posted prices, are compared on where to get naltrexone online.