Lorazepam Dosing for Adults
For anxiety in adults, start with lorazepam 0.5-1 mg orally 2-3 times daily (maximum 4 mg/24 hours), with elderly or debilitated patients requiring reduced doses of 0.25-0.5 mg (maximum 2 mg/24 hours). 1, 2
Standard Dosing by Indication
Anxiety Disorders
- Initial dose: 2-3 mg/day divided into 2-3 doses, with most patients requiring this range 2
- Usual therapeutic range: 2-6 mg/day in divided doses, with the largest dose taken at bedtime 2
- Maximum daily dose: Up to 10 mg/day may be used, though 2-6 mg/day is typical 2
- PRN dosing: 0.5-1 mg every 4-6 hours as needed (maximum 4 mg/24 hours) 3
Insomnia Due to Anxiety
- Single bedtime dose: 2-4 mg at bedtime for transient situational stress or anxiety-related insomnia 2
Acute Agitation or Delirium
- Standard dose: 0.5-1 mg orally four times daily as needed (maximum 4 mg/24 hours) 1
- Sublingual administration: Oral tablets can be used sublingually when swallowing is difficult 1
- Parenteral route: 1 mg subcutaneously or intravenously (maximum 2 mg) for severe agitation in oncology settings 3
Nausea/Vomiting (Anticipatory)
- Initial dose: 0.25-0.5 mg orally three times daily 3
- PRN dosing: 0.5-2 mg every 4-6 hours as adjunct to other antiemetics 3
Special Population Adjustments
Elderly or Debilitated Patients
- Reduced initial dosing: 1-2 mg/day in divided doses, adjusted as needed and tolerated 2
- PRN dosing: 0.25-0.5 mg (maximum 2 mg/24 hours) 1
- Rationale: Elderly patients have increased sensitivity to benzodiazepines with higher risk of falls, cognitive decline, and paradoxical agitation 3
Hepatic Impairment
- Advanced liver disease: Reduce initial dose to 0.25 mg orally 2-3 times daily 3
- Metabolic advantage: Lorazepam undergoes glucuronide conjugation rather than hepatic oxidation, making it relatively safer in liver disease compared to other benzodiazepines 4, 5
Renal Impairment
- Dose adjustment: Generally not required for lorazepam itself, though renal disease may prolong half-life and increase volume of distribution 4
Respiratory Compromise
- Reduced dosing: Use lower doses in patients with COPD or pulmonary insufficiency 3
- Contraindication: Severe pulmonary insufficiency is a contraindication except in moribund patients 3
Dose Titration and Administration
Increasing Doses
- Gradual escalation: Increase dosage gradually to avoid adverse effects 2
- Evening dose first: When higher dosage is indicated, increase the evening dose before daytime doses 2
Discontinuation
- Gradual taper required: Use a gradual taper to reduce risk of withdrawal reactions 2
- If withdrawal occurs: Pause the taper or increase dosage to previous level, then decrease more slowly 2
Pharmacokinetic Considerations
Absorption and Onset
- Oral bioavailability: 90% or more with rapid absorption 4
- Time to peak concentration: Approximately 2 hours after oral administration 5
- Intramuscular route: Rapidly absorbed with similar bioavailability to oral 4
Duration of Action
- Elimination half-life: 8-25 hours (typically 12 hours), making it an intermediate-acting benzodiazepine 4, 5
- Steady state: Achieved within 2-3 days on multiple-dose regimens 5
- Complete elimination: Within 1 week following last dose 5
Critical Safety Warnings
Contraindications
- Severe pulmonary insufficiency, severe liver disease, and myasthenia gravis (except in moribund patients) 3
Drug Interactions
- Extreme caution with olanzapine: Concomitant use with high-dose olanzapine has resulted in reported fatalities 3
Adverse Effects
- Paradoxical agitation: Occurs in approximately 10% of patients 3
- Long-term risks: Regular use can lead to tolerance, addiction, depression, and cognitive impairment 3
- Respiratory depression: Rates of 10-11% in clinical studies, though lower than placebo in some contexts 6
Outpatient Use Limitation
- Not recommended for short stays: Should not be used in patients with expected hospital stay less than 72 hours or in outpatient settings due to prolonged duration of action 7