Oral Liquid Lorazepam (Ativan) Dosing
For oral liquid lorazepam, the standard adult dose is 2 mg, with pediatric dosing at 0.05-0.1 mg/kg (maximum 20 mg), though specific oral liquid formulations require careful attention to preparation method and concentration. 1
Adult Dosing
Oral liquid lorazepam for sedation/anxiolysis in adults is dosed at 2 mg, which may be repeated every 30-60 minutes as needed. 1 The commercially available oral solution is typically supplied at 2 mg/mL concentration. 2
- Peak plasma concentrations occur approximately 2 hours after oral administration 3
- Duration of effect is 6-8 hours 1
- Onset of sedative effect occurs 20-30 minutes after oral administration 1
Pediatric Dosing
For children, oral lorazepam dosing is weight-based at 0.05-0.1 mg/kg, with specific age-related considerations. 1
Age-Specific Recommendations:
- Children under 6 years: May require up to 1 mg/kg (maximum 20 mg) 1
- Children 6-12 years (prepubertal): 0.05-0.1 mg/kg 1
- Adolescents (13+ years): 0.5-1 mg per dose 1
- Older adolescents (>16 years): May receive adult dosing of 2 mg 1
Doses may be repeated every 30-60 minutes for acute agitation. 1
Critical Preparation Considerations
The method of liquid preparation significantly impacts dosing accuracy—commercially available solution is strongly preferred over extemporaneous preparations. 4
Preparation Options (in order of preference):
Commercially available lorazepam solution (2 mg/mL): Most accurate (101.5 ± 3.1% accuracy, 3.0% imprecision) 4
Pharmacist-prepared suspension (1 mg/mL): Acceptable but less accurate (109.2 ± 4.9% accuracy, 4.5% imprecision) 4
Bedside tablet slurry: Least reliable and NOT recommended (91.2 ± 7.8% accuracy, 8.6% imprecision) 4
The tablet slurry method, where crushed tablets are mixed with water at bedside, produces significant dosing variability due to rapid particle settling and lack of homogeneity. 4
Storage and Stability
Commercially available lorazepam oral solution requires refrigeration and protection from light, with a 90-day beyond-use date once opened. 5
- When repackaged into oral syringes, lorazepam oral solution (2 mg/mL) maintains >90% concentration for 60 days at both room and refrigerated temperatures 5
- This allows for unit-dose preparation in automated dispensing systems 5
Special Populations and Warnings
Respiratory Precautions:
Lorazepam causes respiratory depression and should be used with extreme caution in patients with respiratory compromise. 1
- Paradoxical agitation may occur, especially in younger children and those with developmental disabilities 1
- Monitor oxygen saturation continuously 1
- Have reversal agents (flumazenil) and respiratory support equipment immediately available 1
Contraindications:
Drug Interactions:
Reduce lorazepam dose by 50% when coadministered with probenecid or valproate. 2 Conversely, female patients on oral contraceptives may require dose increases. 2
Pharmacokinetics
- Absorption half-life: 25 minutes (range 10-43 minutes) 6
- Elimination half-life: 14.2 hours (range 8.4-24 hours) 6, 3
- Time to peak concentration: 2-3 hours 6, 3
- Steady-state: Achieved within 2-3 days of multiple dosing 6, 3
- Metabolism: Conjugation with glucuronic acid to inactive metabolites 3
- Excretion: 70-75% excreted as glucuronide conjugate in urine 3
Common Pitfalls
Avoid using large doses of commercially available solution containing polyethylene glycol and propylene glycol in pediatric intensive care settings, as this may cause diarrhea and propylene glycol toxicity. 4 In such cases, pharmacist-prepared suspensions without these excipients are preferred despite slightly reduced accuracy. 4
Never use bedside-prepared tablet slurries for critical dosing situations due to unacceptable dosing variability. 4