Benzodiazepine Dose Conversion: Lorazepam to Diazepam
2 mg IV lorazepam (Ativan) is approximately equivalent to 10 mg IV diazepam, representing a 1:5 conversion ratio.
Conversion Ratio
The standard conversion between these two benzodiazepines is based on their relative potencies:
- Lorazepam 2 mg IV = Diazepam 10 mg IV 1
- This represents a 1:5 ratio (lorazepam:diazepam) 1
- Some sources suggest lorazepam 2-2.5 mg is equivalent to diazepam 10 mg, but the 2 mg:10 mg conversion is most commonly used 1
Clinical Context for Dosing
For Procedural Sedation
- Diazepam: Initial dose 5-10 mg IV over 1 minute, with 10 mg typically sufficient for most endoscopic procedures 2
- Lorazepam: Typical procedural sedation doses are 0.05-0.10 mg/kg IV (maximum 4 mg per dose) 3
For Status Epilepticus
- Lorazepam: 4 mg IV given slowly at 2 mg/min, may repeat once after 10-15 minutes if seizures continue 4
- Diazepam: 5 mg IV initially, with additional 5 mg if needed 4
- The 1:5 ratio is maintained in this indication, though lorazepam is generally preferred for status epilepticus due to longer duration of anticonvulsant effect 5
Important Pharmacologic Differences
While the dose conversion is 1:5, these medications differ significantly in their clinical profiles:
- Onset: Diazepam peaks at 2-3 minutes, while lorazepam has an 8-15 minute latent period with peak effects at 15-30 minutes 6
- Duration: Lorazepam has a longer duration of clinical effect and amnesia compared to diazepam 1, 6
- Metabolism: Diazepam has active metabolites that can accumulate in renal insufficiency, while lorazepam does not 7
Critical Safety Considerations
- Both medications cause dose-dependent respiratory depression, especially when combined with opioids 2
- Monitor oxygen saturation and be prepared to provide respiratory support with either agent 3
- Dose reductions of 20% or more are required in elderly patients (>60 years) and those with significant comorbidities 2
- Lorazepam formulations contain propylene glycol, which can cause metabolic acidosis and acute kidney injury at cumulative doses as low as 1 mg/kg/day 7