Emergency Treatment of Seizures: Lorazepam and Diazepam Dosing
For emergency treatment of seizures, the initial dose of lorazepam (Ativan) is 0.05-0.10 mg/kg IV/IM (maximum 4 mg per dose), and diazepam (Valium) is 0.1-0.3 mg/kg IV (maximum 10 mg per dose). 1
Initial Benzodiazepine Selection and Dosing
Lorazepam (First-line)
- IV/IM: 0.05-0.10 mg/kg (maximum: 4 mg per dose) 1
- May repeat dose every 10-15 minutes if needed for continued seizures 1
- For adults with status epilepticus, the FDA-approved dose is 4 mg given slowly (2 mg/min), with an additional 4 mg if seizures continue after 10-15 minutes 2
- IM administration (0.2 mg/kg, maximum 6 mg) is effective when IV access is unavailable 3
Diazepam (Alternative)
- IV: 0.1-0.3 mg/kg every 5-10 minutes (maximum: 10 mg per dose) 1
- Administer over approximately 2 minutes to avoid pain at IV site 1
- Rectal: 0.5 mg/kg up to 20 mg (useful when IV access is unavailable) 1
- IM route is not recommended due to tissue necrosis risk 1
Administration Considerations
Lorazepam Administration
- IV administration should be slow to minimize respiratory depression 1, 2
- Prior to IV use, lorazepam injection must be diluted with an equal amount of compatible diluent 2
- For IM administration, deep intramuscular injection is recommended 3
- Refrigeration is required for lorazepam, which may limit access in some settings 4
Diazepam Administration
- Administer IV diazepam slowly (over ~2 minutes) to avoid pain at injection site 1
- Rapid IV administration may precipitate seizures 1
- Rectal diazepam can be used when IV access is unavailable, with absorption within 5-20 minutes 5
Efficacy Considerations
- Lorazepam has a longer duration of anticonvulsant activity (several hours) compared to diazepam (20-30 minutes) 6
- In overt generalized convulsive status epilepticus, lorazepam was successful in 64.9% of cases compared to 55.8% for diazepam plus phenytoin 7
- Diazepam should be followed immediately by a long-acting anticonvulsant (such as phenytoin/fosphenytoin) due to its short duration of action 1
- Recent research shows intramuscular midazolam may be more effective than IV lorazepam in prehospital settings 8
Monitoring and Safety
- Monitor oxygen saturation and respiratory effort closely with both medications 1
- Be prepared to provide respiratory support, as both drugs can cause apnea 1
- There is an increased risk of respiratory depression when benzodiazepines are combined with other sedative agents 1
- Flumazenil may be administered to reverse life-threatening respiratory depression, but will also counteract the anticonvulsant effects and may precipitate seizures 1
- Maintain patent airway and have ventilatory support equipment available 2
Special Populations
- Elderly patients require dose reduction (0.05-0.1 mg/kg for lorazepam) due to decreased drug metabolism and higher risk of respiratory depression 3
- Patients over 50 years may experience more profound and prolonged sedation with intravenous lorazepam 2
- Paradoxical excitement or agitation may occur, especially in younger children 1
Common Pitfalls
- Underdosing benzodiazepines in status epilepticus can lead to continued seizure activity 2
- Failure to prepare for potential respiratory depression, especially when combining with other sedatives 1
- Not following lorazepam with a long-acting anticonvulsant when treating status epilepticus 1
- Administering diazepam IM (should be avoided due to tissue necrosis risk) 1
- Not monitoring vital signs closely, particularly respiratory rate and oxygen saturation 3