Naltrexone in alcohol dependence

Note: This information should be read in conjunction with the product information literature from the distributor.

Naltrexone is used to reduce incidence and severity of relapse to alcohol consumption in alcohol dependent individuals (see also Acamprosate in alcohol dependence factsheet).

1. Mode of action

Naltrexone is a µ opioid receptor antagonist with high receptor affinity that reduces the reinforcing euphoric reward of alcohol. In patients with alcohol dependence naltrexone treatment supports abstinence and reduces severity of relapse into alcohol use.

2. Indications

Naltrexone is a PBS Authority item for alcohol dependent individuals as part of a comprehensive treatment plan with a goal of abstinence. A plan that involves regular GP review will meet PBS requirements. 

3. Treatment considerations

Naltrexone has a slightly larger effect size than acamprosate but has more adverse effects including headache, nausea, fatigue and lowered mood. These effects are usually transient and rarely necessitate cessation of therapy. 

Naltrexone’s main interaction is with opioids and it should not be used in patients requiring opioid therapy.

Naltrexone is not recommended in acute hepatitis or liver failure, and liver function tests should be monitored during therapy. It is inadvisable to commence treatment with Naltrexone in patients whose ALT is >3-5 x normal.

Naltrexone may be given in combination with acamprosate and there is some evidence for benefit of this combination over monotherapy. 

The safety of naltrexone in pregnancy has not been established.

The usual dose of naltrexone is 50mg daily, usually commenced day 4 – 7 from last drink. Patients are usually commenced on a half tablet (25mg) daily for the first 3-5 days to minimize side-effects. There are no specific ill-effects from alcohol consumption during treatment with naltrexone and patients do not need to be advised to cease therapy if they relapse. Discontinuation of Naltrexone does not result in a withdrawal syndrome.

Patients should be provided with a medication alert card, indicating that they are taking naltrexone, to carry with them.

For further information see package insert, contact the distributor or contact DACAS.


The opinions expressed herein are ours and not necessarily those of the manufacturers and distributors.

This information is a general guide for the use of naltrexone in the management of alcohol dependence. Consultation with a specialist service (e.g. DACAS) is recommended for patients using multiple drugs or with serious medical or psychiatric conditions. The drug doses given are a guide only and should be adjusted to suit individuals.