What is the recommended IV dose of Ativan (lorazepam) for acute anxiety?

IV Lorazepam Dosing for Acute Anxiety

For acute anxiety in adults, administer IV lorazepam 2 mg total (or 0.02 mg/lb [0.044 mg/kg], whichever is smaller) given slowly at a rate not exceeding 2 mg per minute. 1

Standard Dosing Protocol

• Initial dose: 2 mg IV is the recommended starting dose for sedation and anxiety relief in most adult patients 1
• Alternative weight-based calculation: 0.044 mg/kg may be used, but should not exceed 2 mg in standard cases 1
• Maximum infusion rate: Never exceed 2 mg per minute to avoid adverse cardiovascular effects 1
• Dilution requirement: Must be diluted with an equal volume of compatible solution (Sterile Water for Injection, Normal Saline, or 5% Dextrose) immediately prior to IV use 1

Special Population Adjustments

Elderly Patients (>50 years)

• Do not exceed the initial 2 mg dose in patients over 50 years of age 1
• Elderly patients have decreased drug metabolism and higher risk of respiratory depression, requiring lower doses 2

Patients with Hepatic or Renal Disease

• No dose adjustment needed for acute single-dose administration in hepatic disease 1
• Renal disease: No adjustment for acute dosing, but exercise caution with frequent repeated doses 1

Administration Technique

• Dilute lorazepam 1:1 with compatible solution and mix by gentle inversion (do not shake vigorously) 1
• May inject directly into vein or into tubing of existing IV infusion 1
• Inject slowly over at least 1 minute for a 2 mg dose (maximum rate 2 mg/min) 1

Critical Safety Monitoring

Respiratory depression is the primary concern and requires immediate availability of:

• Oxygen supplementation 3
• Airway management equipment 1
• Artificial ventilation capability 1
• Continuous oxygen saturation monitoring 4

Cardiovascular monitoring:

• Blood pressure may decrease, particularly with rapid administration 3, 2
• Vital signs should be monitored continuously 1

Clinical Efficacy Timeline

• Onset of anxiolytic effect: Discernible within 10 minutes of IV administration 5
• Peak effect: Patients typically free of anxiety symptoms within 60 minutes 5
• Duration: Effects last several hours, supporting single-dose efficacy for acute episodes 5

Drug Interactions Requiring Dose Reduction

• Reduce dose by 50% when coadministered with probenecid or valproate 1
• Reduce doses of other CNS depressants (opioids, sedatives, anesthetics) when used concomitantly 1
• Increased risk of apnea when combined with other sedative agents 3, 6

Common Pitfalls to Avoid

• Never administer undiluted IV lorazepam - must be diluted 1:1 before injection 1
• Never exceed 2 mg/min infusion rate - rapid administration increases risk of hypotension, bradycardia, and respiratory depression 3, 1
• Do not use oral route post-procedure - decreased responsiveness creates aspiration risk 4
• Avoid in patients with acute narrow-angle glaucoma or severe respiratory insufficiency 1

When Higher Doses May Be Considered

In select patients under 50 years where greater sedation is beneficial, doses up to 0.05 mg/kg (maximum 4 mg total) may be administered, but this significantly increases respiratory depression risk and should only be used with enhanced monitoring 1. This higher dosing is more appropriate for procedural sedation rather than simple anxiety management 1.

Reversal Agent Availability

• Flumazenil should be available to reverse life-threatening respiratory depression if it occurs 4, 2
• Note that flumazenil will reverse all benzodiazepine effects and may precipitate withdrawal or seizures in dependent patients 4