First-Line Treatment for Acute Seizures in Adults According to NSW Practice Guidelines

The first-line treatment for acute seizures in adults is intravenous lorazepam at a dose of 4 mg given slowly (2 mg/min). 1

Initial Management of Acute Seizures

Lorazepam 4 mg IV is the preferred first-line agent for acute seizures in adults, with success rates of approximately 65% in terminating generalized convulsive status epilepticus 2
If seizures continue or recur after a 10-15 minute observation period, an additional 4 mg IV dose of lorazepam may be administered 1
When IV access is not immediately available, alternative routes for benzodiazepine administration include buccal, intranasal, or intramuscular routes 3
Equipment necessary to maintain a patent airway should be immediately available prior to intravenous administration of lorazepam 1

If seizures persist despite optimal dosing of benzodiazepines, second-line agents should be administered:

Intravenous phenytoin or fosphenytoin (20 mg/kg at maximum rate of 50 mg/min) is a recommended second-line agent 4, 5
Intravenous valproate (20-30 mg/kg over 5-20 minutes) is an alternative second-line agent with similar efficacy to phenytoin but fewer adverse effects like hypotension 4, 5
Intravenous levetiracetam (30 mg/kg over 5 minutes) is another acceptable second-line option with reported success rates of 68-73% 4, 5

For seizures that continue despite first and second-line treatments:

Propofol (2 mg/kg bolus, followed by 3-7 mg/kg/hour infusion) can be used, though respiratory support will be required 5
Midazolam (0.15-0.20 mg/kg IV loading dose, followed by continuous infusion) is another option for refractory status epilepticus 5
Phenobarbital (20 mg/kg IV over 10 minutes) may also be considered, with reported success rates of approximately 58% 4, 5

Continuous vital sign monitoring is essential, particularly respiratory status and blood pressure 5
Airway patency must be assured and respiration monitored closely, with ventilatory support available if needed 1
Simultaneously search for and treat underlying causes of seizures, including hypoglycemia, hyponatremia, hypoxia, drug toxicity, and systemic or CNS infection 4

The Veterans Administration cooperative trial showed that first-line treatment success rates were: lorazepam 64.9%, phenobarbital 58.2%, diazepam/phenytoin 55.8%, and phenytoin alone 43.6% 6, 2
Valproate has been shown to be at least as effective as phenytoin for refractory status epilepticus, with potentially fewer adverse effects 4
In comparative studies, valproate controlled seizures in approximately 88% of cases versus 84% with phenytoin, with significantly less hypotension in the valproate group 4

Respiratory depression is the most common and clinically relevant side effect of benzodiazepines, occurring in up to 18% of patients 3
Phenytoin/fosphenytoin administration may be associated with cardiac arrhythmias, hypotension, and tissue injury at the injection site 7
The aggregate response rate to second-line agents for patients who do not respond to first-line agents is only about 7%, highlighting the importance of appropriate first-line treatment 6
Status epilepticus requires more than just anticonvulsant administration—it requires observation and management of all parameters critical to maintaining vital function 1