I Tried Naltrexone and It Didn't Work. Why?
By Rethink Drink.
If naltrexone didn't work for you, you're far from alone.
And it isn't a verdict on you.
When we dig into what happened, it usually comes down to a few things: how it was taken, how long it was given, and whether anyone was supporting you alongside it.
And sometimes, honestly... it just doesn't work for that person. It helps many people. Not everyone.
Maybe you bought it online, or a doctor prescribed it.
You took it for a few weeks, on your own. Felt rough. Saw nothing change...
And the box went in a drawer.
On calls, people often tell us they've tried everything. AA, a detox, apps, months without a drink... and naltrexone on its own. So when it "didn't work", it landed as one more piece of evidence that they were the problem.
You're not the problem.
But it's worth understanding what happened before you write it off, or before you try anything again.
In short
Two methods, two goals. On the NHS, naltrexone is usually taken daily, once you've stopped drinking, to help you stay stopped. The Sinclair Method uses it before drinking, while you're still drinking, so the desire weakens over time. Both are legitimate. Mixed up on your own, it's hard to tell if it "worked".
It's slow, and it works best with support. In the key Finnish trial, the difference only became clear late on, and naltrexone beat a placebo only for people who also had coping-skills support.
A plateau is common. Drinking comes down, then stalls. Usually because the habits haven't been worked on yet.
Feeling rough isn't always the tablet. Side effects are real. So is the tiredness that comes with drinking less.
It doesn't work for everyone. The research shows a real effect, but a moderate one.
What now: speak to a prescriber before you restart anything. Don't change how you take it on your own.
Check first: if your body depends on alcohol, stopping or cutting down too fast can be dangerous. Speak to your GP or local alcohol service before you change anything.
Why didn't naltrexone work for me?
We can't answer that for you. Nobody can, from a web page.
But we can tell you what comes up again and again when people tell us it didn't work... And the research behind each one.
Read them as information, not a verdict. A treatment that didn't work the first time is data. It isn't a judgement on you.
A common point when people think it's not working is when they drink what they used to, or their drinking plateaus after seeing a reduction... In our coaching, this happens for most people, as often the habit hasn't been worked on. Taking a tablet cannot change our habits.
I took it every day. Was that wrong?
Not wrong. Just possibly a different method from the one you wanted.
Naltrexone can be used in two completely different ways:
The usual NHS way. Taken daily, once you've already stopped drinking, to help you stay stopped. This is how it's licensed in the UK, and it's a first-choice medicine in UK guidance.
The Sinclair Method. Taken before drinking, at a time your prescriber sets, while you're still drinking. Over time, the desire for alcohol weakens, and you drink less, or stop if you choose to. In the UK, this use is off-label.
Same medicine. Different plan. Different goal.
If your goal was to drink less, and you took it every day while drinking as you always had, with no plan and nobody to check in with, you weren't really following either method as it was designed.
That doesn't mean daily naltrexone can't help someone who's still drinking. Some trials have used it that way. It means that, on your own, you had no way of knowing what "working" was supposed to look like.
This is the most common thing we hear. Taken daily. Taken alone.
...See Naltrexone for alcohol in the UK
How you take it is always your prescriber's decision. Never work it out from a forum.
What if I sometimes drank without taking it?
This is the one that catches people out on The Sinclair Method.
When you drink, endorphins land on opioid receptors in the brain... and that's the reward. Naltrexone blocks those receptors, so the endorphins have no place to land. Do that again and again, and the relationship with alcohol weakens. Researchers call that extinction.
So every drink without it in place hands the reward back... and reinforces the old relationship, habit and behaviour.
The Finnish researchers wrote that naltrexone was most effective when it was paired with drinking.
The days you most want a drink are often the days it's easiest to "forget" the tablet.
That isn't a character flaw. It's the habit protecting itself.
Be honest with yourself, and your prescriber, about how often that happened. Not to beat yourself up... Just to know whether the method got a fair run.
How long should naltrexone take to work?
Longer than most people give it.
We're conditioned to expect a medicine to work like paracetamol. Take it... feel better by the afternoon.
This isn't that. You're teaching your brain something new.
In that Finnish trial (Heinälä and colleagues, 2001), 121 people who were still drinking when they started were followed for 32 weeks. The difference between naltrexone and the placebo grew as the study went on, and only became statistically significant in the last 8 weeks.
Months, not weeks.
And the early signs are small. Your awareness grows, and the voice saying drink less, or don't drink, gets clearer. A drink going warm before you finish it. A glass left half full. Not thinking about a drink until later than usual.
If you were waiting for a big moment, you might have walked straight past the small ones.
...See How long does The Sinclair Method take to work?
Does naltrexone work without support?
This is the one we'd underline twice.
In that same trial, for people who also had coping-skills sessions, 27% on naltrexone had no return to heavy drinking across the 32 weeks, against 3% on the placebo.
For people given only general support, naltrexone didn't beat the placebo at all.
Read that again... The support made the difference.
And the NHS has never meant it to work alone, either. In the UK, naltrexone is licensed as part of a wider treatment programme that includes psychological support.
... Why does it matter so much?
Because taking a tablet cannot change our habits.
Same drink. Same glass. Same seat. Same time of night...
The medicine works on the reward. Your habits, triggers, mindset and environment need a different kind of work. That's the real work, and it's where support comes in.
...See Why support matters with The Sinclair Method
Did it work for a while, then stall?
This is the most common "it's stopped working" moment.
Your drinking came down. Then it stopped coming down. Or you're back to drinking around the same as before.
That's not uncommon. And it usually isn't the medicine giving up. It's the habit that hasn't been touched yet.
Some people try to push through it on willpower. They cut right down, overnight. It can feel brilliant for a fortnight.
But you're back to not drinking while still wanting to. And when that slips, a lot of people describe the urge coming back harder. In animal research, that's called the alcohol deprivation effect. How far it applies to people is still debated, but many people recognise the pattern in themselves: months without a drink, then one glass because there was an occasion... and it's a bottle.
And if your body depends on alcohol, cutting down too fast can be dangerous. That needs a doctor, not willpower.
Speed isn't the goal. Staying consistent with the method is, and working on one habit at a time as you go.
...See Quick tips for The Sinclair Method
I didn't like how it made me feel. Was it the tablet?
Maybe. Side effects are real, and we're not going to pretend otherwise.
The UK patient leaflet lists nausea, headaches, trouble sleeping, anxiety and feeling weak among the very common ones. The Cochrane review also found tiredness and daytime sleepiness among naltrexone's side effects.
But it isn't always the tablet.
Passing out isn't sleep.
Alcohol can help you drop off. But a review of sleep-lab studies (in healthy volunteers) found it disrupts the second half of the night. If you've been drinking most nights for years, you may not have had a proper night's sleep in a long time.
So when the first lighter nights come, your sleep can take a while to settle. You feel shattered... And the tablet gets the blame.
Feeling flat can be part of cutting down, too, not only the tablet. Does naltrexone block all pleasure?
One more to rule out. If you cut down and got shakes, sweats, sickness or couldn't sleep, that can be alcohol withdrawal. Please speak to a doctor.
Tablet, cutting down, or withdrawal? It's VERY hard to untangle on your own. That's exactly what a prescriber is for.
...See Naltrexone side effects, in plain English
What if naltrexone just doesn't work for me?
It might not. And we'd rather tell you that than pretend.
That Cochrane review brought together 50 trials, with nearly 7,800 people. Naltrexone lowered the risk of returning to heavy drinking compared with a placebo, to 83% of the placebo group's risk. The authors described the effect as moderate. Most of those trials used it daily.
A real effect. Not a large one. And it varies from person to person.
Some trials found no benefit at all. One large US study of 627 veterans with long-term, severe alcohol dependence found naltrexone did no better than a placebo over a year (and fewer than half the doses were actually taken, in every group).
Even our own famous 78% figure needs context. It comes from Dr Sinclair's own clinics in Finland, not from a controlled trial. Controlled trials show a smaller, but real, effect. And results vary.
...Here's what the research really shows, including what that figure can't tell you.
So if you gave it a fair run, the right way, with support, and nothing changed... that's useful to know. It isn't failure. It points you somewhere else.
And there are other routes. Other medicines, like acamprosate, or nalmefene, which is licensed in the UK to help some people cut down. Your local NHS alcohol service. Mutual-aid groups like AA or SMART Recovery. They all help people every day.
...See Alcohol treatment options in the UK
Matt, our co-founder, had his own route that didn't fit. Six months sober with AA, while he was taking acamprosate alongside. In his words: "I wasn't drinking. But I wasn't free from it either... I couldn't stop thinking about it. And I was miserable."
Is it my fault it didn't work?
No.
Most of the reasons on this page aren't about willpower at all. They're about information nobody gave you, a method that wasn't explained, and doing something hard on your own.
Matt knows that feeling of "is this not working any more?"
He had it himself, a few months into The Sinclair Method. A proper wobble, on the drive home from the workshop.
What that day showed him wasn't about the tablet. It was about the habits and triggers still sitting there.
When he broke it down, he hadn't realised how much of a trigger his thirst and hunger actually were. From then on, hydration and eating well became part of his routine.
That's Matt's experience, certainly not a promise of yours.
...He tells the full story in How long does The Sinclair Method take to work?
What should I do now?
Speak to a prescriber before you restart anything.
Not a forum. Not a box in the cupboard. Your GP (General Practitioner), or a regulated private prescriber.
Tell them:
What you took, where it came from, and how you took it.
What happened, including side effects and how you slept.
How your drinking is now, honestly.
Every other medicine you take, including painkillers. Naltrexone doesn't mix with opioid painkillers like codeine or tramadol.
They decide whether naltrexone is right for you now, and how and when you take it.
If you bought it from a website that didn't ask for a prescription, say so. There's no way of knowing what was in that box. The General Pharmaceutical Council says the only way to confirm a pharmacy is legally operating in Great Britain is to check its register.
...See Where to get naltrexone in the UK
Please don't adjust it yourself. Not more, not less, not a different time. If something isn't working, that's a conversation, not a DIY fix.
And this time, get support around it. Whoever it's from.
...See Can I get naltrexone from my GP or the NHS?
...And if they've said no: My GP said no. What now?
Common questions
Does naltrexone stop working after a while?
The UK product information says people don't build up a tolerance to its blocking effect. If it seems to have stopped working, look at what else changed: stress, routines, missed tablets, other medicines. Then talk it through with your prescriber and coach.
Should I take more if it isn't working?
No. Never change how much you take, or when, on your own. That's your prescriber's decision.
How long should I give it before deciding?
That's a judgement for you and your prescriber. On The Sinclair Method, change is usually measured in months, not weeks.
Is it worth trying naltrexone again?
Whether to try again, or try something else, is a decision for a prescriber. Two things worth telling them: how you took it, and whether you had support.
If you'd like support from us
Rethink Drink is a UK coaching service built around The Sinclair Method. Our programmes include a consultation with an independent prescribing doctor, who decides whether treatment is suitable for you. Any prescription is dispensed by an independent partner pharmacy. Our coaches work with you, week by week, on everything around it.
And whatever happens, you can talk to someone today. Drinkline, the national alcohol helpline, is free and confidential: 0300 123 1110.
Please look after yourself
This page is here to help you understand your options. It isn't medical advice, and it can't replace a conversation with a doctor who can ask qualifying questions.
Before you change how much you drink or start any medication, speak to your GP or a prescriber.
We really hope this post helps. If you have any questions, you can contact us here.
The Rethink Drink team
Sources
Heinälä P, Alho H, Kiianmaa K, Lönnqvist J, Kuoppasalmi K, Sinclair JD. Targeted use of naltrexone without prior detoxification in the treatment of alcohol dependence: a factorial double-blind, placebo-controlled trial. Journal of Clinical Psychopharmacology, 2001. https://www.cpsp.pitt.edu/wp-content/uploads/2021/01/3-VIIH3-2001-Targeted-Use-of-Naltrexone.pdf
Rösner S and colleagues. Opioid antagonists for alcohol dependence. Cochrane Database of Systematic Reviews, CD001867. https://www.cochrane.org/CD001867/ADDICTN_opioid-antagonists-alcohol-dependence
Krystal JH and colleagues. Naltrexone in the treatment of alcohol dependence. New England Journal of Medicine, 2001. https://doi.org/10.1056/NEJMoa011127
emc (electronic medicines compendium). Naltrexone hydrochloride film-coated tablets: Summary of Product Characteristics and patient leaflet. https://www.medicines.org.uk/emc/product/8968/smpc
Department of Health and Social Care. UK clinical guidelines for alcohol treatment, chapter 10: pharmacological interventions. https://www.gov.uk/guidance/clinical-guidelines-for-alcohol-treatment/10-pharmacological-interventions
NICE. Alcohol-use disorders: diagnosis, assessment and management of harmful drinking and alcohol dependence (CG115). https://www.nice.org.uk/guidance/cg115
NICE. Nalmefene for reducing alcohol consumption in people with alcohol dependence (TA325). https://www.nice.org.uk/guidance/ta325
Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB. Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical and Experimental Research, 2013. https://doi.org/10.1111/acer.12006
NHS. Alcohol use disorder. https://www.nhs.uk/conditions/alcohol-use-disorder/
Sherwood Forest Hospitals NHS Foundation Trust. How to reduce your alcohol intake safely (patient leaflet, revised May 2025). https://sfh-tr.nhs.uk/media/liontmlf/pil202505-06-hrais-how-to-reduce-your-alcohol-intake-safely.pdf
General Pharmaceutical Council. Buying medicines safely online. https://www.pharmacyregulation.org/standards/guidance/buying-medicines-safely-online
