What is the equivalent dose of Valium (diazepam) when converting from Ativan (lorazepam)?

Lorazepam to Diazepam Conversion

When converting from lorazepam (Ativan) to diazepam (Valium), use a ratio of 1:5, meaning 1 mg of lorazepam is equivalent to approximately 5 mg of diazepam.

Conversion Ratios and Evidence

The conversion between these two benzodiazepines is well-established in clinical practice. According to comparative studies, lorazepam is approximately 5 times more potent than diazepam:

• 1 mg lorazepam ≈ 5 mg diazepam 1
• 2-2.5 mg lorazepam ≈ 10 mg diazepam 1

This conversion ratio is supported by clinical research that has directly compared the sedative effects of these medications.

Practical Conversion Algorithm

1. Calculate the total daily dose of lorazepam
2. Multiply by 5 to determine the equivalent diazepam dose
3. Adjust for pharmacokinetic differences:
   • Diazepam has a longer half-life than lorazepam
   • Diazepam may require divided dosing initially

Important Pharmacokinetic Differences

When converting between these medications, consider these important differences:

• Onset of action: Diazepam has a more rapid onset than lorazepam
• Duration of effect: Lorazepam effects last longer than diazepam at equivalent doses 1
• Absorption differences: Diazepam has better oral absorption compared to IM administration, while lorazepam has consistent absorption by both routes 1
• Metabolism: Diazepam has active metabolites with long half-lives, while lorazepam has no active metabolites

Clinical Considerations

Route of Administration

• If converting from IV lorazepam to oral diazepam, consider that oral diazepam has good bioavailability
• For IM administration, lorazepam has more reliable absorption than diazepam 1

Special Populations

• In elderly patients or those with hepatic impairment, consider starting with lower diazepam doses
• For patients with renal impairment, lorazepam may be preferred as it has no active metabolites

Potential Pitfalls

1. Underdosing: Using an incorrect conversion ratio may lead to withdrawal symptoms
2. Timing issues: Due to differences in onset and duration, timing of administration may need adjustment
3. Cross-tolerance: Patients with tolerance to one benzodiazepine may show cross-tolerance to others
4. Withdrawal risk: Abrupt conversion without proper dosing may precipitate withdrawal symptoms

Example Conversion

For a patient taking lorazepam 2 mg three times daily (6 mg total):

• Equivalent diazepam dose: 6 mg × 5 = 30 mg diazepam daily
• Initial regimen might be diazepam 10 mg three times daily

Remember that individual patient factors may necessitate dose adjustments based on clinical response and side effects.