Medication Reference Card: Alcohol Use Disorder

Naltrexone

Oral (50 mg/day) · PBS-listed

Dr Basanth Kenchaiah
FRANZCP · Cert. Addiction Psych. · MBBS · DPM · DNB (Psychiatry) Addiction Psychiatrist v1.2 · October 2026

Audience Clinicians

Purpose Prescribing quick-reference for naltrexone in alcohol use disorder (AUD).

Key messages

Mu-opioid receptor antagonist: reduces reward from alcohol without aversive reaction with drinking
Oral 50 mg/day; Sinclair Method for harm reduction approach
Contraindicated with concurrent opioid use; require 7–10 day opioid-free period before initiation

Particularly useful when comorbid with:

OPRM1 A118G variant / strong family history of AUD Comorbid opioid use disorder Impulsive / reward-seeking profile Harm reduction goal (Sinclair Method) Comorbid stimulant use disorder

For Clinicians

Mechanism

Mu-opioid receptor antagonist. Reduces dopaminergic reward from alcohol by blocking endogenous opioid release in the nucleus accumbens. No aversive reaction with alcohol consumption.

Dosing

Oral: 50 mg/day. Consider the Sinclair Method (taken 1 hour before drinking) for harm-reduction approach. Requires opioid-free period before initiation (7–10 days for short-acting opioids).

Evidence

Moderate-to-high quality evidence. Meta-analyses show NNT ≈ 12 for preventing return to heavy drinking. COMBINE trial (JAMA 2006) and McPheeters et al. JAMA 2023 systematic review confirm benefit.

Cautions

Contraindicated with concurrent opioid use (precipitates withdrawal)
Avoid in acute hepatitis or severe liver disease (ALT/AST >5× ULN)
May worsen dysphoria in some patients
Requires opioid-free period before initiation: 7–10 days (short-acting), 10–14 days (long-acting/methadone)