Naltrexone

Basic naltrexone information

• INN (international nonproprietary name): naltrexone
• Brand names available in the United Kingdom: Naltrexone Accord
• ATC code: N07BB04
• Forms and strengths: tablet (oral) 25 mg, 50 mg, 100 mg
• Manufacturers in the United Kingdom: Accord Healthcare
• Registration status in the United Kingdom: Prescription only (Rx)
• OTC / Rx classification: Prescription only (Rx)

Legal status and availability in the UK

Naltrexone is a prescription-only medicine (POM) in the UK, and pharmacists, GPs and specialist addiction teams usually work together on treatment.

For patients who want convenient access, our online pharmacy can supply naltrexone without a prescription, with discreet delivery to the United Kingdom in 9–21 days.

Clinical effectiveness in the UK

How does naltrexone fit into NHS treatment if the person is already ready to change?

In UK pathways, it is commonly used for alcohol use disorder and for opioid dependence after detox, with counselling, relapse-prevention work, and monitoring built around it.

The usual oral dose is 50 mg daily, although some supervised regimens use 100 mg on Monday, Wednesday, and Friday, or 150 mg on Friday.

For detoxed opioid dependence, treatment often starts with a 25 mg test dose before moving to 50 mg daily.

That test dose is there for safety, because starting too soon after opioid use can trigger severe withdrawal.

The people most likely to do well are those who can stick to treatment, attend follow-up, and get help quickly if nausea, cravings, or missed doses become a problem.

Common reasons for stopping include feeling sick, forgetting tablets, and not having easy access to local services or review appointments.

Some patients also say they do not want medicine to interfere with work, family life, or concentration, especially in the first few days.

In the UK, outcomes often depend on whether the person can access structured follow-up through NHS portals, specialist alcohol services, or a pharmacist who is confident with addiction medicines.

That is where pharmacy input can make a real difference, especially for e-prescriptions and repeat supply checks.

Indications and expanded uses

What is naltrexone actually for, and what should not be mixed up with it?

MHRA-regulated use centres on detoxed opioid dependence and alcohol dependence, and the medicine sits in ATC class N07BB04.

It is an opioid antagonist and it is prescription-only, so it should not be treated like an over-the-counter recovery aid.

Approved use

Treatment of alcohol dependence and detoxed opioid dependence under prescription supervision.

Off-label use

Use outside the core approved addiction indications, usually in specialist settings.

Low-dose naltrexone (LDN)

A much lower-dose approach that is not the same as standard dependence treatment and should not be confused with NHS addiction prescribing.

Off-label use attracts some interest, but regulated dependence treatment remains the main evidence-based role.

Composition and brand landscape

In practice, the active ingredient is naltrexone hydrochloride, and the familiar oral strength in the UK is 50 mg, although 25 mg and 100 mg tablets also exist.

UK patients may see generic pack labelling or the full name naltrexone hydrochloride on the box.

That is normal and does not change the active medicine inside the pack.

Contraindications and special precautions

When should naltrexone not be started at all?

There are a few absolute barriers that matter more than anything else: current physiologic opioid dependence, a positive opioid urine test before starting, acute hepatitis or liver failure, and known hypersensitivity to naltrexone or excipients.

That is why clinicians check opioid status carefully before a first dose.

• Precipitated withdrawal: can happen if opioids are still present.
• Mood changes: some patients report anxiety, insomnia, or low mood.
• Liver monitoring: liver function tests are important in people with liver disease or other risk factors.
• Pregnancy and breastfeeding: use only if the benefit clearly outweighs the risk.
• Driving and work: dizziness and nausea can affect concentration early on.

Patients sometimes ask a pharmacist for reassurance because they are worried about withdrawal or feeling unwell at work.

That is a sensible conversation to have before starting, especially if there is any history of liver disease, renal impairment, or concurrent hepatotoxic medicine use.

Dosage guidelines

How much should be taken, and for how long?

The answer depends on the indication, and the regimen.

Children under 18 are not usually recommended to take it because safety and efficacy are not established.

Older adults do not need a routine dose change, but they do need closer monitoring if organ impairment is present.

Hepatic or renal impairment does not usually mean a standard dose change, but it does mean more caution and follow-up.

In UK practice, pharmacists and addiction services often explain dosing alongside e-prescription supply, so patients know exactly when to start and what to do if a tablet is missed.

Interactions overview

What medicines or substances matter most with naltrexone?

The main concern is opioids, because naltrexone blocks opioid receptors and can trigger withdrawal if opioids are still in the system.

That includes prescribed opioid painkillers and illicit opioid use.

If anything unusual happens, especially liver-related symptoms or marked mood change, MHRA Yellow Card reporting is appropriate.

Comparable medicines and preferences

Which medicine suits which person best?

Naltrexone is an opioid antagonist, while methadone and buprenorphine are opioid agonist or partial agonist options.

That difference matters because it shapes who prefers tablets, who needs supervised opioid maintenance, and who wants a non-opioid option after detox.

• Naltrexone: useful for alcohol dependence and detoxed opioid dependence; taken as tablets.
• Acamprosate: often used to support abstinence in alcohol dependence.
• Disulfiram: used for alcohol aversion therapy in selected patients.
• Nalmefene: another option for alcohol dependence.
• Methadone or buprenorphine: more suited to opioid substitution treatment.

People may prefer naltrexone if they want a non-opioid maintenance option and are already detoxed.

The drawbacks are daily adherence, liver monitoring, and the need to plan ahead for opioid pain relief.

Frequently asked questions

How long does naltrexone take to work? It starts blocking opioid receptors after dosing, but the practical benefit builds when it is taken regularly and combined with support.

Can I drink alcohol while taking it? Alcohol is not a direct interaction, but drinking can weaken treatment goals and delay recovery.

What if I miss a dose? Take it as soon as remembered, unless it is close to the next dose; do not double up.

Is it safe with painkillers? Opioid painkillers may not work properly, so any pain plan should be discussed with a clinician before starting.

Guidelines for proper use

How should naltrexone be used safely day to day?

Good counselling is usually what stops a sensible prescription turning into a bad experience.

• How to take: confirm opioid-free status first, then take tablets exactly as prescribed.
• What to avoid: opioid medicines, recreational opioids, and unnecessary liver strain from other hepatotoxic medicines.
• When to seek help: severe nausea, worsening mood, yellowing of the skin or eyes, or signs of withdrawal.
• Where to get support: GP review, NHS alcohol services, local addiction teams, and pharmacist check-ins.

Tablets should be stored at 20°–25°C and protected from moisture.

Keep the conversation open with the pharmacist, because that is often where UK patients get the most useful reassurance about safety, storage, and follow-up.

Delivery across the United Kingdom