Benzodiazepine Dose Equivalency: Clonazepam to Lorazepam
0.25 mg of clonazepam is approximately equivalent to 0.5 mg of lorazepam.
Standard Conversion Ratio
The evidence supports a 2:1 conversion ratio between lorazepam and clonazepam when converting between these benzodiazepines 1:
- Clonazepam 1 mg = Lorazepam 2 mg
- Therefore, clonazepam 0.25 mg = lorazepam 0.5 mg
This conversion is derived from comparative studies examining benzodiazepine equivalencies in clinical practice, where clonazepam doses of 1-2 mg were compared to haloperidol 5-10 mg, while lorazepam 2 mg was shown to be equivalent to similar haloperidol doses 1.
Clinical Context for Conversion
The conversion ratio applies most reliably to:
- Anxiolysis and sedation purposes 2
- Acute agitation management 1
- Seizure control, though timing of onset differs 3
Important pharmacokinetic differences to consider:
- Lorazepam has a faster onset of action (peak effect at 3-5 minutes IV) compared to clonazepam 1
- Clonazepam has a longer duration of action than lorazepam 2
- Both drugs undergo different metabolic pathways, with lorazepam being directly conjugated and eliminated 4
Practical Dosing Considerations
When converting from clonazepam 0.25 mg to lorazepam, the 0.5 mg lorazepam dose should be adjusted based on:
- Route of administration: IV lorazepam acts more rapidly than oral formulations 2
- Clinical indication: For status epilepticus, weight-based dosing (0.05-0.10 mg/kg, maximum 4 mg) is preferred over fixed conversions 5, 6
- Patient factors: Age, liver function, and concomitant medications affect metabolism of both drugs 4
Critical safety warning: Both medications can cause respiratory depression, especially when combined with other sedatives or opioids 5, 4. Monitor oxygen saturation and be prepared to provide respiratory support 1, 5.