What is the recommended dose of Ativan (lorazepam) for a 120kg patient experiencing alcohol withdrawal?

Lorazepam Dosing for Alcohol Withdrawal in a 120kg Patient

For a 120kg patient experiencing alcohol withdrawal, administer lorazepam 2-4 mg IV/PO/IM every 4-8 hours as needed based on withdrawal severity, with a typical total daily dose of 6-12 mg/day, though weight-based considerations may warrant starting at the higher end of this range. 1

Initial Dosing Strategy

• Start with lorazepam 2-4 mg IV/PO/IM every 4-8 hours, with the total daily dosage typically ranging from 6-12 mg/day 1
• For a 120kg patient, consider initiating at 3-4 mg per dose given the larger body mass, though standard dosing ranges remain appropriate as benzodiazepine dosing for alcohol withdrawal is primarily symptom-driven rather than strictly weight-based 1
• Lorazepam is specifically preferred over long-acting agents like diazepam in patients with hepatic dysfunction, advanced age, respiratory compromise, or obesity 1

Symptom-Triggered vs. Fixed-Schedule Dosing

• Use symptom-triggered dosing guided by CIWA-Ar scores rather than fixed schedules to minimize total benzodiazepine exposure and treatment duration 2, 1, 3
• Administer lorazepam when CIWA-Ar scores ≥8, with scores ≥15 indicating severe withdrawal requiring more aggressive treatment 4
• Symptom-triggered regimens reduce total benzodiazepine consumption by approximately 84% (37.5 mg vs 231.4 mg oxazepam equivalent) and shorten treatment duration from 62.7 to 20.0 hours compared to fixed-schedule dosing 3

Critical Adjunctive Treatment

• Administer thiamine 100-500 mg IV immediately before any glucose-containing fluids to prevent Wernicke encephalopathy 2
• Continue thiamine 100-300 mg/day throughout withdrawal and for 2-3 months following resolution 2
• Replace magnesium, as it is commonly depleted in chronic alcohol use and essential for symptom management 2

Advantages of Lorazepam for This Patient

• Lorazepam lacks active metabolites and has intermediate-acting properties, making it safer than diazepam in patients with potential liver dysfunction, obesity (as in this 120kg patient), or respiratory compromise 1
• Multiple administration routes (IV, PO, IM) provide flexibility if the patient is uncooperative or unable to take oral medications 1
• Hospital admission rates and 1-week outcomes are equivalent between lorazepam and diazepam (17.5% vs 18.7% admission rate), demonstrating comparable efficacy 5

Escalation for Severe or Refractory Withdrawal

• If symptoms persist despite initial dosing, increase frequency to every 2-4 hours rather than increasing individual doses 1
• In severe cases, lorazepam doses can be escalated substantially—case reports document up to 1,600 mg/day in refractory delirium tremens, though this is exceptional 6
• For benzodiazepine-refractory cases in the ICU, consider dexmedetomidine as adjunctive therapy only, never as monotherapy, since it does not prevent seizures or delirium tremens 2

Treatment Duration and Tapering

• Limit benzodiazepine use to 10-14 days maximum due to high abuse potential in patients with alcohol use disorder 4, 1
• Begin tapering by 10-20% per day once withdrawal symptoms resolve 1
• Gradually increase dosing intervals from every 4-8 hours to every 8 hours, then every 12 hours, then every 24 hours, then every other day before discontinuation 1

Monitoring Requirements

• Continuously monitor vital signs for autonomic instability including tachycardia, hypertension, fever, and sweating 2
• Assess for dangerous complications: dehydration, electrolyte imbalances (especially magnesium), infection, hepatic encephalopathy, and gastrointestinal bleeding 2
• Watch for paradoxical agitation, which occurs in approximately 10% of patients receiving benzodiazepines 4

Common Pitfalls to Avoid

• Never administer glucose-containing IV fluids before thiamine, as this can precipitate acute Wernicke encephalopathy 2
• Do not use anticonvulsants for alcohol withdrawal seizures, as these are rebound phenomena with lowered seizure threshold, not genuine seizures requiring anticonvulsant therapy 2
• Avoid switching to long-acting benzodiazepines like diazepam or chlordiazepoxide in this 120kg patient if there is any suspicion of hepatic dysfunction, as dose-stacking can occur 2

Post-Acute Management

• Psychiatric consultation is mandatory after stabilization for evaluation, ongoing treatment planning, and long-term abstinence strategies 2, 1
• Consider relapse prevention medications such as acamprosate, naltrexone, disulfiram, or baclofen after withdrawal completion 2
• Avoid naltrexone if alcoholic liver disease is present due to potential hepatotoxicity 2