Gambling addiction medication: what is prescribed and what the evidence shows

No medicine is approved for gambling addiction anywhere. The US Food and Drug Administration has approved none for gambling disorder, the European Medicines Agency has approved none, and the UK has none licensed for it. Every prescription written for gambling is off-label: a drug licensed for something else, used for this. The opioid antagonists naltrexone and nalmefene have the most trial evidence behind them, and England’s NICE guideline recommends considering naltrexone, but only after a full course of psychological therapy has not worked, or when relapses keep repeating.

Medication is added to therapy, not swapped for it. NICE tells clinicians to consider continuing psychological therapy alongside naltrexone, because the evidence was not judged strong enough to put any drug first. Nothing on this page is a prescribing instruction: which drug, what dose, whether it suits you at all and how it is monitored are decisions for a doctor who has your medical history in front of them.

Why every prescription for gambling is off-label

The licence a drug holds is specific. Naltrexone tablets are licensed in the United States for the treatment of alcohol dependence and for blocking the effects of opioids; the long-acting injection, Vivitrol, is licensed for alcohol dependence and for preventing relapse to opioid dependence after detoxification. Gambling appears in neither. Nalmefene is licensed in the European Union as Selincro, authorised on 24 February 2013 for reducing alcohol consumption in adults with alcohol dependence — not for gambling. In the United States, the approved nalmefene products are all for reversing the effects of opioids and treating opioid overdose. The American Psychiatric Association states the position for patients plainly: there are no FDA-approved medications to treat gambling disorders.

Off-label prescribing is legal and routine across medicine. It means no regulator has reviewed that drug for that use, so the prescriber carries the responsibility for the decision and usually documents why. NICE flagged this explicitly: in January 2025, naltrexone for harmful gambling was an off-label use. Off-label is not the same as unlicensed or experimental: the drug itself has been through full regulatory review, and its safety profile is known, just for a different condition.

What the trials show, drug by drug

The evidence base is small. The 2022 Cochrane review of medication for disordered and problem gambling found 17 randomised trials with 1,193 participants in total, and graded almost all of the findings low or very low certainty, on small trials, high risk of bias, and people with psychiatric comorbidities generally excluded.

Everything else — N-acetylcysteine, memantine, modafinil, disulfiram, gabapentinoids, GLP-1 drugs, ketamine — sits at the level of single small studies or case series. A 2026 review in Frontiers in Pharmacology that went through 22 drug categories concluded that naltrexone and nalmefene remain the most evidence-based options, and that medication for gambling disorder is otherwise off-label and experimental.

Why UK guidance backs naltrexone and not nalmefene

The drug with the largest number in the meta-analysis is not the drug in the guideline, and the reason is instructive. The NICE committee looked at both. It recommended naltrexone because the doses used in the gambling trials were similar to the doses already approved in the UK for opioid and alcohol relapse prevention, and because committee members had clinical experience of using it at those doses. It did not recommend nalmefene because the doses used in the gambling studies were much higher than the dose licensed in the UK for alcohol dependence, and because the committee had no clinical experience of using it.

Familiarity and a known dose range decided it, not effect size. That also explains why a clinician outside England may reach a different conclusion about nalmefene, and why NICE simultaneously issued research recommendations on where medication belongs in the care pathway and who benefits most — questions the current evidence does not answer.

Who might be offered medication

NICE recommendation 1.5.16 sets two triggers: consider naltrexone to reduce gambling severity if psychological therapy has not achieved the desired outcomes after an appropriate course has been completed, or if the person has repeated relapses despite having received an appropriate course of psychological therapy. Therapy comes first, and by the guideline’s logic a course has to actually be completed before the second step is on the table.

Co-occurring conditions change the picture, and this is where most real prescribing happens. Someone who drinks heavily as well as gambles may be offered naltrexone on-label for the alcohol dependence, with any effect on gambling a secondary hope. Someone with a bipolar spectrum disorder is a different case again: the one positive lithium trial in gambling was confined to that group, and improvement in gambling severity tracked improvement in mood. An SSRI prescribed for depression treats the depression. None of these is a gambling medication in the licensing sense.

Side effects and cautions

Tolerability is a real constraint, not a footnote. In the Cochrane review, discontinuation because of adverse effects was highest for the opioid antagonists, between 10% and 32% of participants across trials. Nausea is the usual early complaint on naltrexone; dry mouth and constipation were also commonly reported.

Two cautions matter more than the rest, and both are on the naltrexone label as well as in NICE’s recommendations:

• Opioids. NICE says to check the person is not taking opioids before starting naltrexone, and to advise avoiding opioids while on it. Naltrexone can precipitate withdrawal in anyone not fully opioid-free. After stopping it, opioid tolerance is reduced, so a dose previously tolerated can cause life-threatening overdose — the US label records fatal cases. This includes prescription painkillers and over-the-counter codeine, so any doctor, dentist or surgeon treating you needs to know.
• Liver and kidneys. Naltrexone caused liver cell injury in a substantial proportion of people exposed to much higher-than-recommended doses in studies. NICE says to check that kidney and liver function are within normal ranges before starting, to run regular liver function tests during treatment, and to watch for chest pain or palpitations.

NICE sets the course at four to six months with an agreed follow-up plan. The dose and the monitoring schedule belong to the prescriber.

Some medicines can cause gambling problems

This runs the other way and is easy to miss. NICE recommendation 1.1.22 tells assessors to check whether a person’s current medication may be contributing to harmful gambling, naming aripiprazole and medicines for Parkinson’s disease, and to consider reducing or optimising them with the relevant specialist. The US label for aripiprazole carries a warning headed “Pathological Gambling and Other Compulsive Behaviors”: post-marketing reports describe intense urges, particularly for gambling, and an inability to control them, sometimes stopping when the dose was reduced or the drug discontinued.

How to ask a doctor, and what the pathway looks like

Ask the question of whoever can refer you: a GP in the UK and Australia, primary care or a psychiatrist in the United States. Four questions are worth writing down beforehand.

• Given my history, is medication worth considering alongside therapy, or is it too early?
• Which drug, and what is it actually licensed for?
• What tests do I need before starting, and how often afterwards?
• Could anything I already take be making the gambling worse?

United Kingdom. The National Prescribing Guidelines for Naltrexone in Gambling Disorder, approved by NHS England’s National NHS Advisory Group for Gambling Disorder on 13 October 2023, set out a shared-care route. An NHS specialist gambling service leads on starting treatment and on the early monitoring; the GP runs baseline tests beforehand and takes over prescribing only once the specialist has established that it works and the dose is stable. So the practical step is a referral into an NHS gambling service rather than a prescription at a single GP appointment. Referral routes are on our UK help page.

United States. There is no approved medication and no national prescribing guideline. Off-label prescribing is a decision for a psychiatrist or an addiction-medicine physician, and it is more likely to come up where there is a co-occurring alcohol or opioid problem. Routes into treatment, including state-funded programmes, are on our US help page.

Australia. Nothing is approved for gambling disorder here either, and services are counselling-led. Start with a GP or the national Gambling Help line; both are on our Australia help page.

What medication does not replace

A drug does not remove access to gambling. Blocking software, self-exclusion schemes and bank gambling blocks do that, and they work on the days when nothing else does — our comparison of blocking apps for iOS and Android covers the options. A drug does not teach the skills that CBT for gambling teaches, and NICE is explicit that therapy should usually continue when naltrexone is started. It does not settle debts, and it does not make relapse impossible; recovery and relapse covers what to do when one happens. Where medication fits in the wider picture is set out in our overview of gambling addiction treatment.