What is the equivalent dose of Valium (diazepam) for a patient taking 0.5 mg of Ativan (lorazepam)?

Equivalent Dose of Valium (Diazepam) for 0.5 mg Ativan (Lorazepam)

The equivalent dose of Valium (diazepam) for a patient taking 0.5 mg of Ativan (lorazepam) is 2.5 mg. 1

Benzodiazepine Equivalence Ratios

• Lorazepam is approximately 4-5 times more potent than diazepam, with a clinical potency ratio where 2-2.5 mg of lorazepam is equivalent to 10 mg of diazepam 1
• Therefore, 0.5 mg of lorazepam is equivalent to approximately 2.5 mg of diazepam (using the 1:5 potency ratio) 1

Clinical Considerations When Converting Between Benzodiazepines

Pharmacokinetic Differences

• Diazepam has a more rapid onset of action compared to lorazepam, but lorazepam has a longer duration of effect 1
• Lorazepam is better absorbed after intramuscular administration compared to diazepam, which has better oral absorption 1

Clinical Applications

• Both medications are effective for various indications including:
  • Status epilepticus management 2, 3, 4
  • Sedation and anxiolysis 5
  • Management of acute agitation 5

Route of Administration Considerations

• For oral administration: 0.5 mg lorazepam ≈ 2.5 mg diazepam 1
• For IV administration: The same equivalence ratio applies, though onset and duration will differ 1

Common Pitfalls in Benzodiazepine Conversion

• Failing to account for the different half-lives when switching between these medications (lorazepam has an intermediate half-life while diazepam has a long half-life due to active metabolites) 5
• Not considering the patient's clinical condition when making the conversion (e.g., liver dysfunction may affect metabolism of diazepam more significantly than lorazepam) 5
• Overlooking the potential for respiratory depression, particularly when combining with other sedative agents 5

Special Populations

• For pediatric patients, dosing should be calculated based on weight, but the same relative potency ratio applies 5
• In elderly patients or those with hepatic impairment, lower doses may be required due to altered drug metabolism 5

Remember that while 0.5 mg lorazepam is approximately equivalent to 2.5 mg diazepam in terms of clinical effect, the onset, duration, and metabolism profiles differ between these medications.