Maximum Dose of Lorazepam (Ativan) in a 6-Hour Period
The maximum dose of lorazepam that can be administered within a 6-hour period is 4 mg per dose, which can be repeated every 10-15 minutes for continued seizures or every 6-8 hours for anxiety/sedation as needed. 1
Adult Dosing Guidelines by Route of Administration
Intravenous (IV) Administration
- Standard dose: 0.05-0.1 mg/kg (maximum 4 mg per dose) 2
- For status epilepticus: Can repeat dose every 10-15 minutes if needed for continued seizures 2
- For sedation/anxiolysis: 0.05-0.1 mg/kg given over 2-3 minutes (maximum 4 mg per dose) 2
Oral Administration
- For anxiety: 2-6 mg/day in divided doses 3
- Single daily dose for insomnia: 2-4 mg at bedtime 3
- Maximum daily dose: Generally 10 mg/day 3
Intramuscular (IM) Administration
- Same dosing as IV: 0.05-0.1 mg/kg (maximum 4 mg per dose) 2
- For acute agitation: 1-2 mg IM, may be repeated hourly as necessary 1
Special Population Considerations
Elderly or Debilitated Patients
- Reduce dose by approximately 50% 1
- Initial oral dosage: 1-2 mg/day in divided doses 3
- For anxiety/agitation: 0.25-0.5 mg orally (maximum 2 mg in 24 hours) 2
Clinical Pearls and Precautions
- Respiratory depression risk increases when lorazepam is combined with other sedative agents 2
- Monitor oxygen saturation and be prepared to provide respiratory support 2
- Flumazenil may be administered to reverse life-threatening respiratory depression, but will also counteract anticonvulsant effects and may precipitate seizures 2
- Paradoxical agitation may occur, especially in younger children 2
Dosing Strategy for Status Epilepticus
Recent research indicates that underdosing lorazepam in status epilepticus increases the risk of progression to refractory status epilepticus. Patients who received less than the recommended 4 mg dose experienced significantly higher rates of progression to refractory status epilepticus compared to those who received the full 4 mg dose (87% vs 62%) 4.
Administration Considerations
- When administering IV lorazepam, give over 2-3 minutes to minimize side effects 1
- Peak effect occurs at 3-5 minutes after IV administration 2
- For oral concentrate formulation, mix with liquid or semi-solid food and consume immediately 3
The evidence strongly supports adhering to the maximum single dose of 4 mg, particularly in emergency situations like status epilepticus, with the option to repeat dosing based on clinical indication and response.