What is the appropriate dose of Ativan (lorazepam) to administer to a patient who has just started having a seizure?

Lorazepam Dosing for Acute Seizure Management

Administer lorazepam 4 mg IV slowly at 2 mg/min immediately for any patient actively seizing. 1, 2

Immediate Administration Protocol

• Give the full 4 mg dose regardless of patient weight (for patients >40 kg), as underdosing significantly increases progression to refractory status epilepticus (87% vs 62%, p=0.03). 3
• Lorazepam demonstrates 65% efficacy in terminating status epilepticus and is superior to diazepam (76% vs 51% single-dose control). 1, 4
• Administer at a rate of 2 mg/min to minimize respiratory depression risk. 2

Critical Pre-Administration Requirements

• Have airway equipment, bag-valve-mask, oxygen, and suction immediately available at bedside before giving lorazepam. 1, 2
• Establish IV access and start fluid resuscitation simultaneously. 5
• Check fingerstick glucose immediately and treat hypoglycemia with 50 mL of 50% dextrose IV if present. 1

Repeat Dosing if Seizure Continues

• If seizures continue or recur after 10-15 minutes, give a second 4 mg dose slowly. 1, 2
• Maximum total lorazepam dose is 8 mg (two 4 mg doses). 1
• Do not give lorazepam if the seizure has already stopped spontaneously—single self-limiting seizures do not require acute benzodiazepine treatment. 1

Escalation to Second-Line Agents

If seizures persist after 8 mg total lorazepam, immediately proceed to second-line therapy: 1

• Valproate 20-30 mg/kg IV over 5-20 minutes (88% efficacy, 0% hypotension risk—best safety profile) 5
• Levetiracetam 30 mg/kg IV over 5 minutes (68-73% efficacy, minimal cardiovascular effects) 1, 5
• Fosphenytoin 20 mg PE/kg IV at max 50 mg/min (84% efficacy, but 12% hypotension risk requiring cardiac monitoring) 1, 5

Special Population Considerations

• Elderly patients (>50 years): Consider lower initial dose of 2 mg IV due to increased sensitivity, though this conflicts with evidence showing underdosing increases refractory status epilepticus. 1, 2 In active seizures, prioritize the full 4 mg dose with enhanced respiratory monitoring.
• Pediatric patients: 0.1 mg/kg IV (maximum 4 mg per dose). 1
• No IV access: IM lorazepam is not preferred but may be used when IV route unavailable (rectal lorazepam shows 100% efficacy when venous access impossible). 2, 4

Monitoring Requirements

• Continuous pulse oximetry and cardiac monitoring throughout treatment. 1
• Prepare for respiratory support—respiratory depression occurs in 3% of lorazepam-treated patients (vs 15% with diazepam). 4
• Monitor for recurrent seizures and consider maintenance anticonvulsant only if seizures recur. 1

Common Pitfalls to Avoid

• Never underdose lorazepam—doses less than 4 mg are associated with 87% progression to refractory status epilepticus versus 62% with full 4 mg dosing. 3
• Never delay treatment to obtain neuroimaging—CT scanning can be performed after seizure control is achieved. 5
• Never use neuromuscular blockers alone—they only mask motor manifestations while allowing continued electrical seizure activity and brain injury. 5
• Never skip directly to third-line agents (pentobarbital, propofol) until benzodiazepines and a second-line agent have been tried. 5

Simultaneous Evaluation for Reversible Causes

While administering lorazepam, immediately search for and treat: 1, 5

• Hypoglycemia (treat with 50 mL 50% dextrose IV)
• Hyponatremia
• Hypoxia
• Drug toxicity or withdrawal syndromes
• CNS infection
• Stroke or intracerebral hemorrhage