Completing an alcohol detox is a significant clinical achievement. But the risk of returning to drinking after detox is high without structured aftercare. Two medications — Acamprosate (Campral) and Naltrexone — have a strong evidence base for reducing relapse risk. Both are NICE-approved for use in alcohol dependence. Understanding how each works helps you have a more informed conversation with your prescriber about which is right for you.
Acamprosate (Campral)
Acamprosate works by stabilising the chemical signalling in the brain that is disrupted by long-term alcohol dependence. Specifically, it modulates the balance between GABA (the brain's main inhibitory neurotransmitter) and glutamate (the main excitatory neurotransmitter) — a balance that alcohol disrupts and that takes weeks to months to normalise after stopping. In practice, Acamprosate reduces the persistent physical discomfort and low-grade craving that many people experience in the weeks and months after detox — sometimes called 'white-knuckling' — making sobriety feel less effortful.
- Taken three times daily as a tablet.
- Most effective when started shortly after completion of detox.
- Does not cause a reaction if alcohol is consumed.
- Suitable for most patients without significant kidney impairment.
- Evidence: reduces relapse rates at 6–12 months compared to placebo.
Naltrexone
Naltrexone works by a different mechanism. It is an opioid receptor antagonist — it blocks the opioid receptors that contribute to the pleasurable and reinforcing effects of alcohol. When alcohol is consumed, the pleasurable effects are significantly reduced, which over time reduces the motivation to drink. It can be used in two ways: abstinence-focused (taken daily to reduce craving and the rewarding effect of any relapse), or as part of the 'Sinclair Method' (taken before drinking, to systematically extinguish the reinforcement of alcohol over time).
- Available as a daily oral tablet or monthly injectable (Vivitrol — not widely available in the UK).
- Suitable for most patients without significant liver disease.
- Cannot be taken by anyone on opioid medication (including codeine, tramadol, or opioid substitution therapy).
- Evidence: reduces heavy drinking days and increases abstinence rates.
- Does not cause physical sickness if alcohol is consumed (unlike Disulfiram/Antabuse).
Which is right for you?
The choice between Acamprosate and Naltrexone depends on several clinical factors:
- Kidney function: Acamprosate requires adequate kidney function. If your kidneys are impaired, Naltrexone is usually preferred.
- Liver function: Naltrexone is metabolised by the liver and should be used with caution if liver disease is significant.
- Opioid use: Naltrexone cannot be used if you take opioid medication of any kind.
- Abstinence goal vs harm reduction: Both medications support abstinence. Naltrexone may be more appropriate if harm reduction (rather than strict abstinence) is the goal.
- Tolerance: Some patients do better with one medication than the other. Your prescriber will advise based on your specific situation.
Both can be combined with therapy
Medication alone is not the whole picture. Both Acamprosate and Naltrexone work best when combined with psychological support — whether that is structured counselling, cognitive behavioural therapy, motivational interviewing, or peer support through AA or SMART Recovery. Ash Rehab can arrange referrals to appropriate ongoing support as part of your aftercare plan.
This article is for general clinical information only. All prescribing decisions are made by a GMC-registered prescriber following individual clinical assessment. Do not stop or start any medication without medical guidance.
