Alcohol — Use and Withdrawal

Per 2020 NHMRC guidance, healthy adults should drink no more than 10 standard drinks a week and no more than 4 standard drinks on any single day, to reduce the risk of alcohol-related harm. Significant dependence with a withdrawal syndrome on cessation is more likely with regular consumption above eight standard drinks/day, and risk increases further with concurrent sedative use.

Intoxication and overdose

Alcohol overdose is potentially fatal — death is usually from vomitus aspiration or respiratory depression. Average lethal BAC is ~0.45–0.5%, though tolerant patients can cope with higher levels, and a much lower BAC can be fatal if combined with other sedatives.

• Observe until BAC falls below 0.2%, ideally continuing until 0.05% with no signs of withdrawal onset.
• Withdrawal can begin at a BAC of 0.1%, usually before it reaches zero.
• BAC typically falls at 0.015–0.02%/hour.
• Treatment is supportive: monitor BAC, airway, consciousness, and oxygen saturation.

Acute alcohol withdrawal

Anxiety, tremor, sweating, nausea/vomiting, agitation, headache, and perceptual disturbance; seizures occur occasionally, and highly dependent patients may progress to withdrawal delirium. Onset is usually 6–24 hours after the last drink, typically lasting up to 72 hours (occasionally weeks).

Many patients need no medication — supportive care (education about the withdrawal process, monitoring, reassurance, a low-stimulus environment) is often sufficient.

If medication is needed, a benzodiazepine loading regimen:

• Diazepam 20 mg orally every 2 hours until 60–80 mg is reached or the patient is sedated. If agitation persists beyond 80 mg or 4 hours, seek medical review and exclude other causes before giving more. Doses over 120 mg should only be given after specialist review to confirm the diagnosis, exclude complications and consider alternatives. Further doses of diazepam are often needed over the following 2–3 days for symptomatic relief, tapered as a fixed reducing regimen or given as required.
• In severe liver disease, prefer a short-acting benzodiazepine without active metabolites (e.g. oxazepam), and involve specialist advice/hospitalisation.

Thiamine — alcohol-dependent patients are typically thiamine-deficient:

• Thiamine 300 mg IM/IV daily for 3–5 days, then 300 mg orally daily for several weeks. Start parenterally, since oral absorption is slow/incomplete in malnourished patients; higher/longer parenteral dosing may be needed for Wernicke encephalopathy or suspected malnutrition.
• Give thiamine before glucose (including IV dextrose) for hypoglycaemia — glucose given to a thiamine-deficient patient can precipitate Wernicke encephalopathy.

Alcohol withdrawal delirium (delirium tremens)

The most severe withdrawal manifestation, usually starting 48–72 hours after cessation and lasting a further 2–3 days (occasionally weeks in severe cases): gross tremor, fluctuating agitation, hallucinations (usually tactile), disorientation, impaired attention, fever, tachycardia, dehydration. A medical emergency requiring hospitalisation — inadequately treated, mortality is high (mainly cardiac). Often associated with infection, anaemia, metabolic disturbance, or head injury, and can co-occur with Wernicke or hepatic encephalopathy.

Treatment principles mirror milder withdrawal (thiamine, diazepam) — very high diazepam doses (>100 mg/day) may be needed, with specialist input.

If an antipsychotic is needed: haloperidol 2.5–10 mg oral or IM, repeated as required, as an adjunct to adequate benzodiazepine dosing, not as monotherapy. For severe symptoms where oral dosing isn’t possible: droperidol 5 mg IM or haloperidol 5 mg IM as a single dose, cautiously. If extrapyramidal effects emerge, treat with benztropine 1–2 mg orally/IM.

Long-term management

Group or individual counselling/support programs, plus relapse-prevention pharmacotherapy:

Disulfiram — for highly motivated, physically fit patients able to commit to abstinence. Don’t start unless the patient fully understands the risk and hasn’t drunk in the previous 24 hours. It blocks alcohol metabolism, so subsequent drinking causes a raised blood acetaldehyde level and an “aldehyde reaction” — intense flushing, sweating, palpitations, tachycardia, dyspnoea, hyperventilation, pounding headache, and sometimes chest pain, restlessness, a sense of impending doom, a BP spike followed by hypotension, or (rarely) cardiorespiratory collapse, seizures, or death. Dose: 200–400 mg daily (1–2 tablets), increasing as needed. Maintenance dosing generally shouldn’t exceed 600 mg daily; some patients need only two or three supervised doses a week.

Acamprosate — reduces the neuronal hyperexcitability of alcohol withdrawal; not effective for the acute phase, but reduces protracted withdrawal symptoms (anxiety, irritability, insomnia, craving). Start alongside a counselling program about a week after the acute withdrawal phase resolves. Dose: <60 kg — 666 mg morning, 333 mg midday, 333 mg night; ≥60 kg — 666 mg three times daily. Renally cleared — contraindicated if creatinine >120 micromol/L.

Naltrexone — blocks the effect of endogenous opioids released by alcohol intake, so drinking becomes less pleasurable (though alcohol-induced impairment is unaffected); some evidence for reduced craving.