What is the recommended dose of Ativan (lorazepam) for a 120kg male with alcohol withdrawal syndrome?

Lorazepam Dosing for Alcohol Withdrawal in a 120kg Male

For a 120kg male with alcohol withdrawal, initiate lorazepam at 2-4 mg IV/SC every hour as needed based on withdrawal severity, with no absolute maximum dose—titrate aggressively to control symptoms, as benzodiazepines are the only proven treatment to prevent seizures and delirium tremens. 1, 2

Initial Dosing Strategy

• Start with 2 mg IV or SC stat (up to 4 mg maximum for initial dose) and repeat every 1 hour as needed for withdrawal symptoms. 3
• For this 120kg patient, consider starting at the higher end (3-4 mg) given his body mass, though weight-based dosing is not explicitly required for lorazepam. 3
• Use CIWA-Ar scores to guide dosing intensity: scores ≥8 indicate need for treatment, and scores ≥15 indicate severe withdrawal requiring aggressive dosing. 1, 2

Critical Advantages of Lorazepam for This Patient

• Lorazepam is the preferred benzodiazepine if hepatic dysfunction is present or suspected, as it has no active metabolites and does not accumulate in liver disease. 1, 2
• In a 120kg male, obesity is a specific indication to switch from chlordiazepoxide to lorazepam (6-12 mg/day range). 1
• Lorazepam can be given IV, SC, PO, or sublingual, providing flexibility in administration routes. 3

Dosing Without Upper Limits

• There is no absolute maximum dose of lorazepam for severe alcohol withdrawal—case reports document up to 1,600 mg in 24 hours for refractory delirium tremens. 4, 5
• If the patient requires two bolus doses within an hour, double any continuous infusion rate if one has been started. 3
• Benzodiazepine resistance in severe withdrawal reflects receptor-site tolerance rather than abnormal drug metabolism, necessitating aggressive dose escalation. 5

Mandatory Adjunctive Treatment

• Administer thiamine 100-500 mg IV IMMEDIATELY before any glucose-containing fluids to prevent precipitating Wernicke encephalopathy. 1, 2
• Continue thiamine 100-300 mg/day throughout treatment and for 2-3 months after withdrawal resolution. 1, 2
• Monitor and replace magnesium, as it is commonly depleted in chronic alcohol use and essential for symptom control. 2

Monitoring Requirements

• Assess vital signs before each dose for autonomic instability: tachycardia, hypertension, fever, and sweating. 1, 2
• Monitor continuously for dangerous complications including dehydration, electrolyte imbalance, infection, hepatic encephalopathy, and respiratory depression. 2
• Be prepared to provide respiratory support, as lorazepam combined with other sedatives increases apnea risk. 3

Common Pitfalls to Avoid

• Do not underdose—lorazepam at 8 mg/day is as effective as chlordiazepoxide 80 mg/day, suggesting higher doses than historically used may be necessary. 6, 7
• Do not continue benzodiazepines beyond 10-14 days due to abuse potential; taper after symptom control is achieved. 1, 2
• Do not substitute anticonvulsants alone for alcohol withdrawal seizures—benzodiazepines are required. 1
• Avoid administering glucose before thiamine, as this can precipitate acute Wernicke encephalopathy. 1, 2

Alternative Considerations

• If lorazepam proves insufficient despite aggressive dosing, consider adding haloperidol 0.5-5 mg every 8-12 hours for severe agitation, though this does not prevent seizures. 8
• For ICU patients with benzodiazepine-refractory withdrawal, dexmedetomidine may be added as adjunctive therapy only, but never as monotherapy. 2

Post-Acute Management

• After stabilization, psychiatric consultation is mandatory for evaluation, ongoing treatment planning, and long-term abstinence strategies. 1, 2
• Consider relapse prevention medications such as acamprosate, naltrexone, baclofen, or topiramate after withdrawal completion. 1, 2