Equivalent Dosage of Ativan (Lorazepam) to Versed (Midazolam) in Oral Form
For oral administration, 1 mg of lorazepam (Ativan) is approximately equivalent to 5 mg of midazolam (Versed). 1
Dosage Equivalence Based on Clinical Guidelines
- Lorazepam 0.5-1 mg orally is recommended for anxiety or agitation in patients who can swallow, with a maximum of 4 mg in 24 hours 1
- For patients unable to swallow, midazolam 2.5-5 mg subcutaneously is the recommended alternative, suggesting a rough 1:5 potency ratio 1
- When converting between these medications, the higher potency of lorazepam must be considered to avoid oversedation 1
Clinical Applications of Dosing Equivalence
- For anxiety management, lorazepam 0.5-1 mg oral dosing is typically equivalent to midazolam 2.5-5 mg 1
- In elderly or debilitated patients, lorazepam doses should be reduced to 0.25-0.5 mg (maximum 2 mg in 24 hours), corresponding to lower midazolam doses 1
- For continuous sedation, lorazepam has been found to be approximately 14 times more potent than midazolam (1.6 mg lorazepam providing similar sedation to 14.4 mg midazolam over 8 hours) 2
Route-Specific Considerations
- Oral midazolam has lower bioavailability (approximately 30-50%) compared to lorazepam (90%), which affects the equivalence ratio 3
- Lorazepam has a longer duration of action (6-8 hours) compared to midazolam (1-4 hours), making dosing frequency different 3
- Sublingual administration of lorazepam tablets is possible as an off-label use when oral administration is challenging 1
Special Patient Considerations
- In patients with renal impairment (eGFR <30 mL/minute), midazolam doses should be reduced by 50% 1
- Patients with hepatic impairment may require dose reduction of both medications due to decreased clearance 3
- Regular alcohol consumers may require higher doses of benzodiazepines due to cross-tolerance 4
Comparative Cost Considerations
- Lorazepam is significantly more cost-effective than midazolam for equivalent sedation, with studies showing approximately 10 times cost savings 5
- The higher potency of lorazepam means less medication is needed for similar clinical effects 2, 5
Common Pitfalls and Cautions
- Combining benzodiazepines with other sedatives increases the risk of respiratory depression and oversedation 3
- Paradoxical agitation can occur in approximately 10% of patients treated with benzodiazepines 1
- Both medications can contribute to delirium, particularly in ICU settings, with midazolam being a stronger independent risk factor 3
- Avoid rapid dose escalation of either medication to prevent respiratory depression 1