Naltrexone - Nalorex

Cutting down on drinking: as part of The Sinclair Method, naltrexone is taken one hour before drinking to block the endorphin reward. Over 3-4 months, the urge to drink fades naturally through pharmacological extinction.

Opioid relapse prevention: After successful detoxification from opioids, naltrexone blocks opioid receptors to prevent the euphoric effects of heroin, codeine, tramadol, fentanyl, and other opioids.

Naltrexone is an opioid receptor antagonist. It binds to mu-opioid receptors in the brain without activating them, effectively blocking endorphins from producing their normal reward signal.

When you drink, your brain normally releases endorphins that create a sense of pleasure and relaxation - this is the reward cycle that drives increased drinking over time. Naltrexone blocks this release. With consistent use before drinking (the TSM protocol), your brain gradually unlearns the association between drinking and reward. This is pharmacological extinction.

Most people notice reduced cravings within 4-6 weeks, with significant reduction over 3-4 months.

Adults who want to drink less using The Sinclair Method. People who have tried willpower-based approaches and found they don’t stick. High-functioning drinkers who want a medical, evidence-based approach.

Not suitable for: People currently taking opioid medications (codeine, tramadol, morphine, methadone, buprenorphine). People with acute hepatitis or significant liver impairment. People with known hypersensitivity to naltrexone.

These medicines are prescription-only and are not dispensed on a form alone. A doctor reviews your assessment and a recent liver result before prescribing.

First prescription: complete the online assessment (£120). A doctor checks your drinking history, your medical history and your liver result, and contacts you if anything else is needed. Once approved, your medication is dispensed and delivered.

Repeat prescription: a shorter doctor-reviewed check, at no charge, confirms it is still working for you and that nothing has changed.

You choose which one applies when you start. If you have had this medication from us before, choose the repeat review. If not, start with the full assessment.

Why the assessment? This medicine interacts dangerously with opioid painkillers and needs liver monitoring, so a doctor reviews every request. That is what the assessment covers, and why a form alone is never enough.

Tracked: Tracked delivery, arrives tomorrow - Free

When it arrives: Every order is sent tracked. Where this page says in post today, it goes out today. Where it says in post tomorrow, it goes out the next working day. On the rare occasions a medicine is unavailable, we will contact you to talk about timing and alternatives.

We dispense clinically equivalent generic medications where available. Prices shown are for the generic version. If you prefer the branded version, let us know in your order form and we will confirm any price difference.

Online assessment by a doctor: £120. After that you order here and a doctor reviews every order at no charge. This is separate from the medication price shown in the order panel, so you only pay for what you need.

Naltrexone: nausea, headache, dizziness, anxiety, insomnia, joint/muscle pain. Acamprosate: diarrhoea, nausea, abdominal pain. Nalmefene: nausea, dizziness, insomnia, headache.

Naltrexone/nalmefene: do not use if you are taking opioids, or have taken them in the last 7 to 10 days. Severe hepatic or renal impairment.

Naltrexone/nalmefene: blocks opioid analgesics - inform all healthcare providers. Alternative pain relief needed.

Limited data in pregnancy. Use only if benefit outweighs risk. Discuss with specialist. Buprenorphine may be continued in pregnancy under specialist supervision to prevent relapse.

Must not be taken with opioid medicines such as codeine, tramadol or morphine: it will completely block any effect of opioids. Liver function tests required before starting and monitored regularly. Most common side effect: mild nausea in the first few days. If you need emergency medical treatment, inform clinicians you are taking naltrexone - opioid pain relief may need higher doses. TSM requires 100% compliance - take naltrexone every time before drinking.