What is the recommended dosage and administration of Inj (Intramuscular/Intravenous) Lorazepam (Ativan) for severe anxiety or sedation?

Injectable Lorazepam Dosing and Administration

For acute agitation or severe anxiety, administer lorazepam 2 mg IV/IM initially, with the option to increase to 4 mg based on clinical response; for status epilepticus, give 4 mg IV at a rate not exceeding 2 mg/min. 1, 2

Dosing by Clinical Indication

Acute Agitation and Severe Anxiety

• Initial dose: 2 mg IV or IM for sedation and anxiety relief 1, 2
• Alternative dosing: 0.02 mg/lb (0.044 mg/kg), whichever is smaller 1, 2
• Maximum dose: 4 mg (0.05 mg/kg up to 4 mg) for patients requiring deeper sedation or amnesia 1, 2
• Reduce dose by 20% or more in elderly patients (generally should not exceed 2 mg in patients over 50 years) 3, 1, 2
• Lorazepam is recommended as effective monotherapy for acute agitation in emergency settings 4

Status Epilepticus

• Standard dose: 4 mg IV given slowly at 2 mg/min for patients ≥18 years and >40 kg 1, 2, 5
• If seizures persist after 10-15 minutes, may repeat with an additional 4 mg IV 1, 2
• Underdosing (<4 mg) significantly increases progression to refractory status epilepticus (87% vs 62%, p=0.03) 5
• IM route is not preferred for status epilepticus due to slower achievement of therapeutic levels, but may be used when IV access unavailable 1, 2

Preoperative Sedation

• IM route: 0.05 mg/kg up to 4 mg maximum, given at least 2 hours before procedure 1, 2
• IV route: 2 mg or 0.044 mg/kg (whichever smaller), given 15-20 minutes before procedure 1, 2

Administration Technique

Intravenous Administration

• Must dilute with equal volume of compatible solution (Sterile Water, Normal Saline, or D5W) before IV use 1, 2
• Mix by gently inverting repeatedly; do not shake vigorously 1, 2
• Maximum injection rate: 2 mg/min 1, 2
• May inject directly into vein or into tubing of existing IV infusion 1, 2
• Clinical effects have 8-15 minute latent period, with peak effects at 15-30 minutes 6

Intramuscular Administration

• Inject undiluted, deep into muscle mass 1, 2
• Absorption is rapid with peak levels at approximately 1.15 hours 7
• Bioavailability is 95.9%, essentially complete 7
• May cause local irritation at injection site 4

Special Population Adjustments

Elderly and Frail Patients

• Reduce dose by 20% or more due to decreased clearance 3
• Use lower doses (0.25-0.5 mg) when combined with antipsychotics 4
• Maximum 2 mg in patients over 50 years for sedation 1, 2

Patients with COPD or Respiratory Disease

• Use lower doses (0.5-1 mg) due to increased risk of respiratory depression 4
• Respiratory depression risk is heightened when combined with opioids 3

Hepatic and Renal Disease

• No dose adjustment needed for acute administration in hepatic disease 1, 2
• No adjustment for acute dosing in renal disease, but exercise caution with frequent repeated doses 1, 2

Drug Interactions

• Reduce lorazepam dose by 50% when coadministered with probenecid or valproate 1, 2
• May need to increase dose in females taking oral contraceptives 1, 2
• Reduce doses of other CNS depressants when used concomitantly 1, 2

Critical Safety Monitoring

Respiratory Monitoring

• Monitor oxygen saturation continuously during administration 8, 3
• Have respiratory support equipment immediately available 8, 3
• Increased risk of apnea with rapid IV administration or when combined with other sedatives 3

Cardiovascular Monitoring

• Watch for hypotension, particularly in elderly or frail patients 8
• Monitor vital signs throughout treatment 1, 2

Status Epilepticus Specific

• Maintain IV infusion, monitor vital signs, ensure unobstructed airway 1, 2
• Have artificial ventilation equipment available 1, 2
• Lorazepam is only initial step; may require additional interventions (e.g., phenytoin) 1, 2
• Identify and correct underlying causes (hypoglycemia, hyponatremia, metabolic derangements) 1, 2

Pharmacokinetic Considerations

• Duration of action: 1-24 hours (longer than midazolam's 1-4 hours) 3
• Elimination half-life: approximately 12.9 hours 7
• Plasma levels similar at 2 hours regardless of route (IV, IM, oral, sublingual) 9, 7
• One-third of peak concentration remains at 24 hours 9

Common Pitfalls to Avoid

• Do not underdose in status epilepticus—doses <4 mg significantly increase progression to refractory status 5
• Do not exceed 2 mg/min IV injection rate to minimize apnea risk 1, 2
• Do not use undiluted for IV administration 1, 2
• Do not combine with high-dose olanzapine due to fatality reports 4
• Benzodiazepines themselves may paradoxically cause or worsen delirium and agitation 4