What is the equivalent dosing of midazolam (Versed) and lorazepam (Ativan) for sedation?

Equivalent Dosing of Midazolam (Versed) and Lorazepam (Ativan)

Midazolam is approximately 2-4 times more potent than lorazepam, meaning 1 mg of lorazepam is roughly equivalent to 2-4 mg of midazolam for sedation purposes. 1, 2

Specific Dose Equivalencies

For Procedural Sedation (Short-Term Use)

• Lorazepam: 1-4 mg IV bolus (0.02-0.04 mg/kg) 3
• Midazolam: 2-5 mg IV bolus (0.01-0.05 mg/kg) 3
• Practical conversion: 1 mg lorazepam ≈ 2 mg midazolam 1

For ICU Sedation (Long-Term Infusions)

• Lorazepam: 0.5-8 mg/h infusion, starting with 1-4 mg bolus 3
• Midazolam: 1-8 mg/h infusion (0.01-0.1 mg/kg/h), starting with 2-5 mg bolus 3
• Observed equipotent ratio: 10 mg midazolam = 0.7 mg lorazepam for long-term sedation 4

Critical Pharmacologic Differences

Onset and Duration

• Midazolam: Onset 1-2 minutes, duration 15-80 minutes 3, 5
• Lorazepam: Onset slower, duration 1-24 hours 3

Clinical Implications by Setting

Choose Midazolam for:

• Procedural sedation requiring rapid onset and short duration 3, 5
• Situations requiring faster titration to desired sedation level 4
• Patients needing quicker awakening after discontinuation 2

Choose Lorazepam for:

• Long-term ICU sedation where easier management of sedation levels is needed 4
• Cost-sensitive situations (lorazepam is approximately 10 times less expensive) 4, 6
• Patients where prolonged amnesia is desired 3

Dosing Adjustments Required

Age-Related Reductions

• Patients >60 years: Reduce midazolam dose by 20% or more 3, 5
• Initial midazolam dose: 1 mg IV (maximum 0.03 mg/kg) over 1-2 minutes 5

Organ Dysfunction

• Hepatic or renal impairment: Reduce both agents by 20% or more 3, 5
• Midazolam clearance significantly reduced in these populations 3

Safety Considerations with Opioid Co-Administration

When combining with opioids (fentanyl, morphine, hydromorphone):

• Synergistic respiratory depression occurs, requiring dose reduction of benzodiazepine 5
• Administer opioid first, then titrate benzodiazepine 5
• Risk of apnea may occur up to 30 minutes after last midazolam dose 3
• Deaths from respiratory depression have been reported with midazolam-opioid combinations 5

Practical Dosing Algorithm

For Acute Procedural Sedation (Healthy Adult <60 years)

1. Start with midazolam 1-2 mg IV over 1-2 minutes 5
2. Additional 1 mg doses at 2-minute intervals until adequate sedation 5
3. Maximum total dose typically 6 mg for routine procedures 3

For ICU Sedation (Benzodiazepine-Naïve Patient)

1. Midazolam: 2 mg IV bolus, then 1 mg/h infusion 3
2. Lorazepam: 1-4 mg IV bolus, then 0.5-8 mg/h infusion 3
3. If symptomatic on infusion: bolus equal to or double the hourly rate 3
4. If two boluses needed in one hour: double the infusion rate 3

Recovery Time Differences

After 72-hour infusion in typical ICU patient:

• Midazolam (light sedation): 3.6 hours to emergence 2
• Lorazepam (light sedation): 11.9 hours to emergence 2
• Midazolam (deep sedation): 14.9 hours to emergence 2
• Lorazepam (deep sedation): 31.1 hours to emergence 2