What dose of Ativan (lorazepam) is equivalent to 5mg of Versed (midazolam)?

Midazolam to Lorazepam Conversion

5 mg of midazolam (Versed) is equivalent to approximately 2-2.5 mg of lorazepam (Ativan). 1

Pharmacological Comparison

• Midazolam is a water-soluble, short-acting benzodiazepine that is 1.5-3.5 times more potent than diazepam with a rapid onset of action (1-2 minutes) and shorter duration of effect (15-80 minutes) 2
• Lorazepam has a slower onset but longer duration of action compared to midazolam, making the conversion important for maintaining appropriate sedation levels 1
• The potency ratio indicates that lorazepam is approximately 2-2.5 times more potent than midazolam on a milligram-to-milligram basis 1, 3

Clinical Implications

• When converting between these medications, consider that midazolam has:

  • Faster onset (1-2 minutes IV) with peak effect at 3-4 minutes 2
  • Shorter duration (15-80 minutes) requiring more frequent dosing 2
  • More rapid clearance, especially in younger patients with normal hepatic function 2

• Lorazepam provides:

  • Longer duration of action, making it more suitable for extended sedation 4
  • More predictable sedation levels in critically ill patients 4
  • More cost-effective option for longer-term sedation needs 3, 4

Dosing Considerations

• For procedural sedation, midazolam is often preferred due to its rapid onset and shorter recovery time 5
• For longer-term sedation, lorazepam may be more appropriate due to its longer duration of action and more predictable sedation levels 4
• When converting from midazolam to lorazepam in critical care settings, an equipotent dose ratio of approximately 10:0.7 (midazolam:lorazepam) has been observed 4

Special Populations

• Elderly patients and those with hepatic or renal impairment require dose reductions for both medications 2
• Patients on concomitant CNS depressants may require lower doses of either medication due to synergistic effects 2
• When either medication is combined with opioids, dose reductions are necessary due to synergistic respiratory depression 2

Clinical Pearls

• Both medications can cause respiratory depression, with midazolam potentially causing apnea up to 30 minutes after administration 2
• Flumazenil can be used as an antidote for benzodiazepine-induced respiratory depression, but its duration of action (approximately 1 hour) may be shorter than the benzodiazepine effect, requiring monitoring for re-sedation 2
• When using either medication for acute agitation in the emergency department, both are considered effective as monotherapy 2