What is the recommended approach for switching a patient from 0.5 mg of Ativan (lorazepam) to Valium (diazepam)?

Switching from Ativan (Lorazepam) 0.5 mg to Valium (Diazepam)

The recommended conversion from 0.5 mg of lorazepam (Ativan) to diazepam (Valium) is 5 mg of diazepam, based on the established equivalence ratio where 1 mg of lorazepam equals approximately 10 mg of diazepam. 1

Conversion Rationale

Lorazepam and diazepam differ significantly in their pharmacokinetic properties, which must be considered when switching between these medications:

• Potency difference: Lorazepam is more potent than diazepam, with 0.5 mg lorazepam equivalent to approximately 5 mg diazepam 1
• Duration of action: Diazepam has a longer elimination half-life (30-40 hours) compared to lorazepam 2
• Onset of action: Diazepam has a faster onset but shorter duration of clinical effect than lorazepam 1

Switching Protocol

1. Initial conversion dose: Replace 0.5 mg lorazepam with 5 mg diazepam

2. Administration schedule:

   • If patient was taking lorazepam once daily, administer diazepam once daily
   • If patient was taking lorazepam multiple times per day, consider dividing the diazepam dose accordingly

3. Monitoring period: Observe patient for 3-5 days after switching to assess for:

   • Withdrawal symptoms (indicating underdosing)
   • Excessive sedation (indicating overdosing)
   • Adjust dosage as needed based on clinical response

Dosage Adjustments

• For elderly patients or those with debilitating disease: Consider starting with a lower dose of diazepam (2-2.5 mg) and titrate gradually as needed 3
• For patients with liver impairment: Use caution as diazepam metabolism may be affected, potentially requiring dose reduction

Important Considerations

• Cross-tolerance: Both medications act on GABA-A receptors, but slight differences in receptor subtype affinity may affect individual response
• Withdrawal risk: Ensure smooth transition to prevent withdrawal symptoms due to the different pharmacokinetic profiles
• Special populations: Use extra caution in elderly patients as benzodiazepines can cause cognitive impairment, delirium, falls, and fractures 2
• Avoid concurrent use with opioids: This combination increases the risk of respiratory depression and fatal overdose 2

Potential Pitfalls

• Underestimating equivalence: Insufficient diazepam dosing may lead to withdrawal symptoms
• Overestimating equivalence: Excessive diazepam dosing may cause oversedation
• Failure to account for half-life differences: Diazepam's longer half-life may lead to accumulation with repeated dosing
• Abrupt switching: Always implement a gradual transition between benzodiazepines

If the patient experiences difficulty with the transition, consider a more gradual approach by temporarily using both medications with progressive reduction of lorazepam while increasing diazepam over several days.