What is the equivalent dose of Klonopin (clonazepam) for Ativan (lorazepam) 10 mg?

Equivalent Dose of Clonazepam for Lorazepam 10 mg

The equivalent dose of clonazepam for lorazepam 10 mg is approximately 5 mg, based on a 1:2 potency ratio where clonazepam is twice as potent as lorazepam.

Benzodiazepine Equivalence Ratios

Benzodiazepines differ in their potency and duration of action. When converting between different benzodiazepines, understanding their relative potencies is essential:

• Lorazepam to clonazepam conversion uses a 2:1 ratio (lorazepam:clonazepam) 1
• This means 2 mg of lorazepam is equivalent to approximately 1 mg of clonazepam

Pharmacological Properties Comparison

Clonazepam

• Long-acting benzodiazepine with elimination half-life of 30-40 hours
• Rapidly absorbed after oral administration with 90% bioavailability
• Maximum plasma concentrations reached within 1-4 hours 2
• Typically dosed at 0.25-2.0 mg daily for anxiety disorders

Lorazepam

• Intermediate-acting benzodiazepine
• Better absorbed after oral administration compared to intramuscular route
• Clinical effects and amnesia begin more rapidly than with some other benzodiazepines
• Typically dosed at 0.5-1 mg for acute anxiety 3

Clinical Considerations for Conversion

When converting from lorazepam to clonazepam, consider:

• Onset and duration differences: Clonazepam has a longer half-life than lorazepam, which may reduce interdose anxiety but could increase risk of accumulation 4

• Side effect profile: Monitor for common side effects including:

  • Sedation (particularly morning sedation)
  • Memory dysfunction
  • Early morning motor incoordination
  • Confusion 2

• Special populations: Use caution in:

  • Elderly patients (start with lower doses of 0.25-0.5 mg)
  • Patients with obstructive sleep apnea
  • Patients with underlying liver disease 2, 3

Practical Conversion Strategy

For a patient on lorazepam 10 mg converting to clonazepam:

1. Calculate equivalent dose: 10 mg lorazepam ÷ 2 = 5 mg clonazepam
2. Consider implementing the conversion gradually to minimize withdrawal symptoms
3. Monitor closely for therapeutic effect and side effects during the transition

Cautions and Monitoring

• Avoid abrupt discontinuation of either medication to prevent withdrawal symptoms
• If discontinuing after prolonged use, implement a gradual taper (e.g., decrease by 0.25 mg weekly) 5
• Monitor for respiratory depression, especially when combined with other CNS depressants 3
• Be aware of potential for dependence with long-term use 6

Common Pitfalls to Avoid

• Underestimating potency differences: Clonazepam is approximately twice as potent as lorazepam, so using a 1:1 conversion would result in excessive dosing
• Ignoring half-life differences: Clonazepam's longer half-life may require less frequent dosing but increases risk of accumulation
• Failure to individualize: While 5 mg is the equivalent dose, clinical factors may necessitate dose adjustments

Remember that 10 mg of lorazepam is a relatively high dose, and careful consideration should be given to whether such high-dose benzodiazepine therapy is appropriate for the patient's condition, with exploration of potential dose reduction strategies when clinically feasible.