In an adult experiencing a seizure, how frequently should 1 mg of intravenous lorazepam (Ativan) be administered?

Lorazepam Dosing for Adult Seizures

For an adult experiencing a seizure, administer 4 mg of intravenous lorazepam slowly (over 2 minutes), and if seizures continue or recur after a 10-15 minute observation period, repeat with an additional 4 mg dose. 1

Initial Dose Administration

• The FDA-approved dose for status epilepticus in adults (≥18 years) is 4 mg IV given slowly at 2 mg/min, not 1 mg 1
• A 1 mg dose is substantially below the recommended therapeutic dose and significantly increases the risk of progression to refractory status epilepticus 2
• Patients receiving less than 4 mg experienced an 87% progression to refractory status epilepticus compared to 62% in those receiving the full 4 mg dose (p=0.03) 2

Repeat Dosing Protocol

• If seizures persist or recur after 10-15 minutes of observation, administer a second 4 mg IV dose 1
• The American Academy of Pediatrics guidelines (applicable to adults) suggest doses may be repeated every 10-15 minutes if seizures continue 3
• Experience with doses beyond two 4 mg administrations is very limited, and additional anticonvulsant therapy should be initiated 1

Critical Safety Measures

• Equipment to maintain a patent airway must be immediately available before IV lorazepam administration 1
• Administer slowly at 2 mg/min to avoid pain at the IV site and reduce risk of respiratory depression 4, 1
• Monitor oxygen saturation continuously and be prepared to provide ventilatory support 1
• Respiratory depression risk increases when lorazepam is combined with opioids or other sedatives 4, 1

Transition to Long-Acting Anticonvulsants

• Lorazepam must be followed immediately by a long-acting anticonvulsant such as phenytoin (18 mg/kg IV over 20 minutes) or fosphenytoin (20 mg phenytoin equivalents/kg) 3
• Lorazepam is rapidly redistributed from the CNS, and seizures often recur within 15-20 minutes without long-acting coverage 4, 3
• If seizures persist after benzodiazepine and phenytoin/fosphenytoin, consider phenobarbital (15-20 mg/kg IV over 10 minutes) 3

Common Pitfalls to Avoid

• Do not underdose: The majority of patients in clinical practice receive less than the recommended 4 mg dose, which significantly increases treatment failure 2
• Do not use flumazenil to reverse sedation in seizure patients, as it will precipitate seizure recurrence 3
• Do not rely on lorazepam alone—status epilepticus requires comprehensive management including vital sign monitoring, IV access, and readiness to address underlying metabolic causes (hypoglycemia, hyponatremia) 1
• The intramuscular route is not preferred for status epilepticus because therapeutic levels are not reached as quickly as with IV administration 1

Duration of Anticonvulsant Effect

• Lorazepam has a longer duration of anticonvulsant activity (up to 72 hours) compared to diazepam (<2 hours) or midazolam (3-4 hours), making it preferred for seizure management 5
• This prolonged effect is related to lorazepam's higher affinity for benzodiazepine receptors in the brain 5