What is the recommended dose of lorazepam (Ativan) injection for acute agitation or anxiety in adults?

Lorazepam Injection Dosing for Acute Agitation and Anxiety in Adults

For acute agitation or anxiety in adults, administer lorazepam 2 mg IV or IM as the initial dose, which can be repeated every 30-60 minutes as needed, with a maximum single dose of 4 mg. 1

Standard Dosing Protocols

Acute Agitation/Anxiety

• Initial dose: 2 mg IV or IM (or 0.02 mg/lb [0.044 mg/kg], whichever is smaller) 1
• Repeat dosing: May repeat every 30-60 minutes as needed 2, 3
• Maximum single dose: 4 mg for most clinical situations 1
• IV administration rate: Must not exceed 2 mg per minute to minimize adverse effects 1

Psychosis with Agitation (Pediatric Guidelines Applicable to Adults)

• Dosing range: 0.05-0.15 mg/kg IM/IV 2
• Maximum single dose: 5 mg 2
• Repeat interval: May repeat hourly as necessary 2

Delirium Management (Oncology Context)

• Standard dose: 1 mg subcutaneously or IV (maximum 2 mg) 4
• Reduced doses required: For elderly, frail patients, those with COPD, or when combined with antipsychotics 2, 4
• Starting dose for elderly: 0.5-1 mg IV/SC 2

Critical Administration Requirements

IV Preparation and Administration

• Mandatory dilution: Must be diluted with an equal volume of compatible solution (Sterile Water for Injection, Normal Saline, or 5% Dextrose) before IV use 1
• Mixing technique: Mix thoroughly by gently inverting repeatedly; do not shake vigorously 1
• Injection technique: Inject slowly with repeated aspiration to ensure proper vascular placement 1
• Stop immediately: If patient complains of pain during injection, as this may indicate intra-arterial injection or extravasation 1

IM Administration

• Technique: Inject undiluted deep into muscle mass 1
• Onset consideration: IM route achieves therapeutic levels more slowly than IV, making it less preferred for emergencies 1

Special Population Adjustments

Elderly Patients (>50 Years)

• Reduced initial dose: Should not exceed 2 mg total 1
• Increased sensitivity: Elderly patients experience more profound and prolonged sedation 1
• Maximum daily dose: 2 mg in 24 hours for elderly or debilitated patients 3
• Higher risk profile: Increased falls, cognitive decline, and paradoxical agitation 4

Hepatic Disease

• Anxiety dosing: Reduce initial dose to 0.25 mg orally 2-3 times daily in advanced liver disease 4
• Acute parenteral dosing: No specific adjustment needed for single-dose administration 1

Renal Disease

• Acute dosing: No adjustment needed for single-dose administration 1
• Caution required: When frequent doses given over short periods 1

Drug Interaction Adjustments

Dose Reduction Required (50% reduction)

• Probenecid coadministration 1
• Valproate coadministration 1

Dose Increase May Be Needed

• Oral contraceptive use in females 1

Combination Therapy Considerations

With Antipsychotics

• Haloperidol + lorazepam: Commonly used combination for severe agitation 2
• Risperidone + lorazepam: Effective for cooperative agitated patients 2, 5
• Olanzapine warning: Fatalities reported with concomitant high-dose olanzapine and benzodiazepines 2, 4
• Dose reduction: Use lower lorazepam doses (0.5-1 mg) when combining with antipsychotics 2

Safety Monitoring and Precautions

Respiratory Monitoring

• Most critical risk: Respiratory depression, especially in status epilepticus treatment 1
• Required equipment: Airway maintenance and artificial ventilation equipment must be immediately available 1
• Vital signs: Monitor continuously during and after administration 1

Cardiovascular Effects

• Hypotension risk: Monitor blood pressure, particularly with repeated doses 2
• QT prolongation: Repeated doses can prolong QT interval and precipitate torsades de pointes 2

Paradoxical Reactions

• Incidence: Approximately 10% of patients experience paradoxical agitation 4, 3
• Dystonic reactions: May occur, particularly with higher doses 2

Contraindications

Absolute Contraindications

• Severe pulmonary insufficiency (except in imminently dying patients) 2, 4
• Severe liver disease (except in imminently dying patients) 2, 4
• Myasthenia gravis (except in imminently dying patients) 2, 4

Post-Administration Considerations

Activity Restrictions

• Duration: Patients should not operate machinery, drive, or engage in hazardous activities for 24-48 hours or until drowsiness subsides, whichever is longer 1
• Prolonged effects: May persist longer in elderly patients, with concomitant drug use, or due to general patient condition 1

Ambulation Precautions

• Fall risk: Exercise care with premature ambulation due to injury risk from falling 1
• Prolonged sedation: Multiple doses increase risk of additive sedation effects, particularly in post-ictal states 1

Common Pitfalls to Avoid

• Underdosing: Doses less than 4 mg in adults >40 kg are associated with increased progression to refractory status epilepticus in seizure management 6
• Rapid IV injection: Exceeding 2 mg/min increases adverse event risk 1
• Failure to dilute IV formulation: Undiluted IV administration is contraindicated 1
• Inadequate monitoring: Respiratory depression can occur rapidly, requiring immediate intervention capability 1
• Scopolamine combination: No added benefit and increases incidence of sedation, hallucinations, and irrational behavior 1