Lorazepam (Ativan) Dosing for Procedural Sedation
For procedural sedation in adults, administer lorazepam 2 mg IV (or 0.044 mg/kg, whichever is smaller) given slowly over 2-3 minutes, with the option to repeat every 10-15 minutes as needed to achieve adequate sedation, not exceeding 4 mg total in patients over 50 years of age. 1
Standard Adult Dosing Protocol
Initial dose: 2 mg IV total or 0.044 mg/kg (whichever is smaller), administered over 2-3 minutes 1
- For patients requiring deeper sedation or amnesia for perioperative events, doses up to 0.05 mg/kg (maximum 4 mg total) may be administered 1
- Allow 3-5 minutes between doses to assess peak effect before redosing to avoid oversedation 2
- Administer 15-20 minutes before the anticipated procedure for optimum effect 1
Critical Dose Reductions Required
Elderly patients (>50 years): Do not exceed initial dose of 2 mg IV; reduce total dose by 20% or more 3, 1
When combined with opioids: Reduce lorazepam dose by 50% due to synergistic respiratory depression 3
Patients with respiratory disease or COPD: Use lower doses due to substantially increased risk of respiratory depression 3
Alternative IM Route (When IV Access Unavailable)
- IM dosing: 0.05 mg/kg up to maximum of 4 mg 1
- Administer at least 2 hours before the anticipated procedure for optimum effect 1
- Note: IM route achieves therapeutic levels more slowly than IV administration 1
Mandatory Safety Monitoring
Continuous monitoring required: 3
- Oxygen saturation
- Respiratory effort and rate
- Blood pressure
Equipment preparation: 1
- Have flumazenil immediately available for reversal (0.01-0.02 mg/kg IV, repeatable at 1-minute intervals to maximum 0.05 mg/kg or 1 mg) 4
- Maintain unobstructed airway
- Have artificial ventilation equipment ready
- Be prepared to provide bag-mask ventilation
Critical Safety Warnings
Respiratory depression risk is highest when: 3
- Lorazepam is administered rapidly IV
- Combined with other sedative agents (especially opioids)
- Used in patients with underlying respiratory disease
- Given to elderly patients
Apnea can occur: There is an increased incidence of apnea when lorazepam is combined with other sedative agents or given rapidly IV 2, 3
Comparison to Other Benzodiazepines for Procedural Sedation
While the 2005 emergency medicine guidelines found that midazolam combined with fentanyl is effective for procedural sedation (Level B recommendation), they did not specifically address lorazepam for this indication 2
Key difference: Lorazepam has a significantly longer duration of action (1-24 hours) compared to midazolam (1-4 hours), which may result in prolonged recovery times 3
Research comparing continuous infusions in ICU patients found lorazepam easier to manage than midazolam for achieving desired sedation levels, though this was in the context of prolonged sedation rather than brief procedures 5, 6
Common Pitfalls to Avoid
- Underdosing: Initial doses below 2 mg may be inadequate for procedural sedation in most adults 1
- Rapid administration: Giving lorazepam faster than over 2-3 minutes significantly increases apnea risk 2, 3
- Inadequate observation time: Redosing before 3-5 minutes can lead to stacked dosing and oversedation 2
- Paradoxical agitation: Benzodiazepines may paradoxically worsen agitation, especially in younger children and some adults 2, 4, 3
Pediatric Considerations
Safety not established: There are insufficient data to support efficacy or make dosage recommendations for lorazepam in patients less than 18 years of age for procedural sedation; therefore, such use is not recommended 1
For pediatric procedural sedation, the 2005 guidelines provide Level A evidence that ketamine can be safely administered to children, and Level B evidence for propofol 2