Disulfiram — Antabuse — is the oldest medication for alcohol use disorder and the most mechanistically unusual. Where naltrexone reduces craving and acamprosate stabilizes the post-acute state, disulfiram does neither. It works only when the patient drinks, and what it does then is produce a severe aversive reaction. The medication's mechanism is the threat of consequence.
- Class
- Aldehyde dehydrogenase inhibitor
- Mechanism
- Inhibits aldehyde dehydrogenase → accumulated acetaldehyde when alcohol consumed → severe aversive reaction (flushing, nausea, vomiting, tachycardia, dyspnea)
- Typical dose
- 250-500 mg/day
- Half-life
- ~60-120 hours (enzyme inhibition persists ~14 days after discontinuation)
- FDA indications
- Alcohol use disorder (deterrent therapy)
- Key adverse effects
- When patient drinks: severe disulfiram-alcohol reaction (can be life-threatening — hypotension, arrhythmia). Without alcohol: hepatotoxicity (monitor LFTs), peripheral neuropathy, psychosis (rare), drug interactions (CYP2E1 inhibition)
Black box: Disulfiram-alcohol reaction can be severe to fatal
Highly motivated patients only. Patient must agree to take it, understand consequences, want the aversive consequence to prevent drinking. Common alcohol-containing products (mouthwash, cooking wine, OTC medications) can trigger reaction — patient education essential. Monitor LFTs. Less commonly used in modern era due to alternatives.
The pharmacology is simple. Alcohol is metabolized first to acetaldehyde, then to acetate. Disulfiram irreversibly inhibits aldehyde dehydrogenase, the enzyme responsible for the second step. When alcohol is consumed, acetaldehyde accumulates and produces a severe physiologic reaction: flushing, severe nausea and vomiting, tachycardia, hypotension, dyspnea, headache, chest pain. The reaction is intensely unpleasant — and can be severe enough to be dangerous, particularly with cardiac comorbidity.
Disulfiram supports abstinence by aversion — it makes drinking alcohol acutely unpleasant by blocking alcohol metabolism.
Mechanism note: Disulfiram is an aversive deterrent, not an anti-craving agent — effective only in motivated, adherent patients (ideally supervised), and contraindicated where the alcohol reaction would be dangerous.
Even small alcohol exposures can trigger the reaction. Mouthwash. Cooking wine. Certain sauces. Some OTC cold medications containing alcohol. The patient on disulfiram must learn the alcohol-content list comprehensively. The inhibition persists for approximately two weeks after the last dose because of the irreversible enzyme inhibition.
Patient selection is everything. Disulfiram has no benefit for the patient who isn't motivated. There's no craving reduction. There's no maintenance support. The medication's mechanism is the patient's own decision to take it knowing the consequences of drinking. For the highly motivated patient who wants the external deterrent — who says "I want a medication that makes drinking impossible" — disulfiram serves that specific purpose. For everyone else, naltrexone or acamprosate fits better.
Side effects without alcohol: hepatotoxicity (monitor LFTs), peripheral neuropathy, occasional psychiatric symptoms, drug interactions through CYP2E1 inhibition. Disulfiram is a real medication with real risks beyond the alcohol reaction.
Modern use is narrow. Naltrexone and acamprosate dominate AUD pharmacotherapy. Disulfiram remains useful for the specific patient profile — highly motivated, comfortable with the aversive mechanism, willing to learn the alcohol-content rules and accept the monitoring.
- Cost
- Generic: ~$30-80/month.
- Generic status
- Generic for decades.
- Formulary typical
- Tier 1-2 generic.
- Access friction
- Drug itself easy. Patient education and motivation are the central friction — the medication only works if the patient takes it knowing the consequences of drinking.
Prescriber tip: Reserve for highly motivated patients explicitly choosing the aversive approach. Document informed consent about the disulfiram-alcohol reaction. Comprehensive alcohol-content education (mouthwash, cooking wine, etc.) at prescription.