What is the appropriate IM dosage of lorazepam for catatonia?

IM Lorazepam Dosing for Catatonia

For catatonia with agitation and pacing, administer lorazepam 2 mg IM initially, which can be repeated every 10-15 minutes if needed, with a typical dosing range of 2-4 mg IM per dose, administered up to three times daily (TID) as clinically indicated. 1

Initial IM Dosing Strategy

• Start with 2 mg IM lorazepam as the initial dose, which aligns with standard preanesthetic IM dosing (0.05 mg/kg up to maximum 4 mg) 1
• The IM route is appropriate when IV access is unavailable, though therapeutic levels are reached more slowly than with IV administration 1
• For catatonia specifically, clinical studies demonstrate that 2 mg IM lorazepam administered once or twice within the first 2 hours achieves an 85.7% complete remission rate 2, 3

TID Dosing Protocol

• Administer 2-4 mg IM every 8 hours (TID) based on clinical response, with doses repeated every 10-15 minutes during acute episodes if catatonic signs persist 4, 1
• The maximum single IM dose should not exceed 4 mg per administration 1
• Total daily doses in catatonia treatment studies have ranged from 3-8 mg/day orally, suggesting that 6-12 mg/day IM (2-4 mg TID) is a reasonable and safe range 5

Critical Monitoring Requirements

• Continuously monitor oxygen saturation due to increased risk of apnea, particularly when benzodiazepines are combined with other sedatives 6, 7
• Respiratory support equipment must be immediately available at bedside 6, 4
• Monitor for hypotension, especially in elderly or frail patients 4, 7
• Watch for paradoxical agitation, which can occasionally occur 4

Response Assessment and Next Steps

• Assess response within the first 2 hours - early response to lorazepam predicts final outcome 5, 2
• If no improvement after 1-2 days of adequate lorazepam dosing (typically 3-6 mg/day for at least 3 days), consider escalation to ECT 5, 8
• Complete resolution of catatonic symptoms occurs in 32-70% of patients with lorazepam alone, with partial improvement in up to 68.7% 5, 8
• If lorazepam fails, diazepam IV infusion (10 mg in 500 mL normal saline every 8 hours) can be considered as an alternative benzodiazepine strategy 2, 3

Common Pitfalls to Avoid

• Do not underdose - inadequate dosing (less than 3 mg/day) reduces response rates significantly 5, 8
• Do not delay ECT consultation if patient fails to respond after 3-5 days of adequate benzodiazepine trial 5, 8
• Avoid oral administration during acute catatonic episodes with decreased responsiveness due to aspiration risk 6
• Do not use flumazenil to reverse sedation, as it will precipitate symptom recurrence 6

Special Population Considerations

• Elderly patients require dose reduction to 0.05-0.1 mg/kg due to decreased metabolism and higher respiratory depression risk 4
• Adjust dosing in patients with hepatic or renal impairment, particularly with frequent repeated doses 4, 1
• No specific dose adjustment needed for single acute doses in renal disease, but exercise caution with repeated dosing 1