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

Benzodiazepine Dose Conversion: Lorazepam to Diazepam

For a patient taking lorazepam (Ativan) 0.5 mg twice daily (total 1 mg/day), the equivalent diazepam (Valium) dose is 5 mg twice daily (total 10 mg/day).

Conversion Ratio and Calculation

• The standard conversion ratio is 1 mg lorazepam = 10 mg diazepam, meaning diazepam requires 10 times the dose to achieve equivalent sedative potency 1.

• For lorazepam 0.5 mg BID (1 mg total daily dose):

  • Multiply by 10: 1 mg × 10 = 10 mg diazepam per day
  • Divide into twice-daily dosing: 5 mg diazepam BID 1

Critical Pharmacokinetic Differences

Diazepam has a significantly longer duration of action than lorazepam, which creates important clinical implications 1:

• Onset of effect: Diazepam produces more rapid clinical effects and amnesia initially 1
• Duration: Lorazepam's clinical effects last longer per dose despite diazepam's longer elimination half-life 1
• Active metabolites: Diazepam accumulates in peripheral tissues and produces active metabolites that can persist, especially in patients with renal insufficiency 2
• Elimination half-life: Diazepam's prolonged half-life results from tissue saturation rather than just hepatic metabolism 2

Dosing Strategy and Monitoring

Start with the calculated equivalent dose (5 mg BID) and monitor closely for the first 48-72 hours 3:

• Assess for breakthrough anxiety symptoms between doses 3
• Watch for excessive sedation, particularly in the evening as diazepam accumulates 2
• Consider adjusting to once-daily dosing after stabilization if the long half-life provides adequate coverage 1

Special Population Adjustments

For elderly or debilitated patients, reduce the initial diazepam dose by 50% (start with 2.5 mg BID) 2, 4:

• Elderly patients are significantly more sensitive to benzodiazepine sedative effects 2
• Benzodiazepine clearance decreases with age 2
• Initial dosing should not exceed 0.5-1 mg lorazepam equivalent (5-10 mg diazepam) twice daily maximum 4

Critical Safety Considerations

Diazepam carries higher risks than lorazepam in specific clinical contexts 2:

• Respiratory depression is more likely when combined with opioids or in patients with baseline respiratory insufficiency 2
• Cardiovascular instability may occur, particularly systemic hypotension in hemodynamically unstable patients 2
• Hepatic dysfunction significantly impairs clearance of both agents, but diazepam's active metabolites compound this problem 2
• Renal insufficiency causes accumulation of diazepam's active metabolites more than lorazepam 2

Common Pitfalls to Avoid

• Do not use a simple 1:5 ratio—the correct conversion is 1:10 1
• Approximately 10% of patients experience paradoxical agitation with benzodiazepines; monitor for increased anxiety or combativeness 2, 3
• Avoid abrupt discontinuation—benzodiazepine withdrawal can occur within 24 hours and requires gradual tapering over 10-14 days 2, 4
• Regular use leads to tolerance, addiction, depression, and cognitive impairment—use the lowest effective dose for the shortest duration 2
• Do not combine with other CNS depressants without careful respiratory monitoring 4

Monitoring Parameters

Assess the following within 2 hours of initial dosing and daily thereafter 4:

• Respiratory rate and oxygen saturation 4
• Level of sedation and cognitive function 2
• Blood pressure and heart rate 2
• Signs of withdrawal if converting from lorazepam (anxiety, tremor, confusion) 4