Benzodiazepine Dose Equivalency: Clonazepam to Diazepam
500 mcg (0.5 mg) of clonazepam is approximately equivalent to 10 mg of diazepam, representing a 1:20 potency ratio.
Equivalency Conversion
The standard benzodiazepine equivalency conversion used in clinical practice establishes that clonazepam is approximately 20 times more potent than diazepam 1. This means:
- 0.5 mg clonazepam = 10 mg diazepam
- 1 mg clonazepam = 20 mg diazepam
This conversion ratio is consistently applied across multiple clinical contexts, including treatment of REM sleep behavior disorder where clonazepam doses of 0.25-2.0 mg are used 1, while diazepam for similar sedative/anxiolytic purposes typically requires 5-20 mg 1.
Clinical Context for Equivalency
Sedation and Anxiolysis
For procedural sedation, diazepam is typically dosed at 5-10 mg IV initially, with up to 20 mg total for endoscopic procedures 1. The equivalent clonazepam effect would be achieved with approximately 0.25-1.0 mg, though clonazepam is less commonly used for acute procedural sedation due to its slower onset 1.
Seizure Control
For status epilepticus, diazepam is dosed at 0.1-0.3 mg/kg IV (maximum 10 mg per dose) in pediatric patients 1. While clonazepam can be used for seizure disorders, the acute seizure protocols typically favor diazepam or lorazepam due to more established dosing guidelines 1.
Important Pharmacokinetic Differences
Despite the 1:20 potency equivalency, these medications differ significantly in their clinical profiles:
Clonazepam Characteristics
- Elimination half-life: 30-40 hours 1
- Onset of action: Slower than diazepam (peak plasma concentration at 1.7-3.1 hours) 2
- Duration of effect: Prolonged, making it suitable for once-daily dosing 1
- Bioavailability: 90% oral, 93% intramuscular 2
Diazepam Characteristics
- Onset of action: Rapid (1-2 minutes IV, peak effect 3-5 minutes) 1
- Duration of effect: Shorter (15-20 minutes for anticonvulsant effect due to rapid redistribution) 1
- Active metabolites: N-desmethyldiazepam prolongs clinical effects 3
Safety Considerations
Both medications carry similar risks that require monitoring:
- Respiratory depression: Particularly when combined with opioids or other sedatives 1
- Dose adjustments needed: Elderly patients, those with obesity, hepatic or renal impairment require 20% or more dose reduction 1, 4
- Monitoring requirements: Oxygen saturation and respiratory effort must be continuously monitored 1, 4
- Reversal agent: Flumazenil (0.01-0.02 mg/kg IV, maximum 0.2 mg) available for severe respiratory depression 1, 4
Clinical Pitfalls
Do not assume interchangeability for acute situations. While the 1:20 equivalency ratio is valid for potency, diazepam's rapid onset makes it preferred for acute seizures, agitation, or procedural sedation 1. Clonazepam's longer half-life makes it more suitable for chronic conditions requiring sustained benzodiazepine effect, such as REM sleep behavior disorder 1.
Avoid flumazenil in patients with seizure disorders or chronic benzodiazepine use, as it may precipitate seizures or acute withdrawal 1, 4.