What is the conversion dose from lorazepam (Ativan) 2mg to clonazepam (Klonopin)?

Benzodiazepine Conversion: Lorazepam 2mg to Clonazepam

Lorazepam 2mg is approximately equivalent to clonazepam 1mg based on relative potency ratios. 1

Conversion Rationale and Evidence

• Lorazepam and clonazepam differ in potency, with clonazepam being approximately twice as potent as lorazepam 1
• Studies comparing benzodiazepines indicate that lorazepam 2-2.5mg is equivalent to diazepam 10mg in terms of sedative effects 1
• Clonazepam has a significantly longer half-life (30-40 hours) compared to lorazepam, which must be considered when switching between these medications 2

Clinical Considerations When Converting

• When converting between benzodiazepines, start with the equivalent dose and monitor closely for clinical response 2
• Clonazepam reaches maximum plasma concentrations within 1-4 hours after oral administration, with a bioavailability of 90% 2
• The recommended therapeutic dose range for clonazepam is typically 0.25mg to 2.0mg, though doses as high as 4.0mg have been reported in some clinical scenarios 2
• Women may require different dosing than men when converting to clonazepam (one study reported women required higher doses than men to control REM sleep behavior disorder symptoms) 2

Important Precautions

• Monitor for side effects after conversion, which may include:
  • Sedation, particularly in the morning 2
  • Impaired coordination 2
  • Confusion, especially in elderly patients 2
  • Memory dysfunction 2
• Use with caution in patients with:
  • Neurodegenerative disorders 2
  • Obstructive sleep apnea (clonazepam at 0.5-1.0mg can worsen sleep apnea) 2
  • Underlying liver disease 2
• Be aware of the potential for drug interactions, particularly with other CNS depressants 2
• The combination of benzodiazepines with certain medications (e.g., clozapine) should be avoided or used with extreme caution due to risk of delirium 3

Tapering Considerations

• If transitioning from lorazepam to clonazepam as part of a tapering strategy, the longer half-life of clonazepam may be beneficial 4
• For patients on long-term benzodiazepine therapy who will eventually need tapering, gradual dose reduction is recommended (e.g., 0.25mg/week for clonazepam) 4
• Monitor for withdrawal symptoms during conversion, which may include anxiety, tremor, nausea, insomnia, sweating, and tachycardia 4

Special Populations

• For elderly patients or those with hepatic impairment, consider starting with a lower equivalent dose (e.g., clonazepam 0.5mg for lorazepam 2mg) 2
• In patients with renal impairment, dose adjustment may be necessary 2