What is the recommended initial dose of Ativan (lorazepam) administered intramuscularly (IM) for an 80-year-old patient experiencing seizure activity?

Intramuscular Lorazepam Dosing for Seizure Activity in an 80-Year-Old Patient

For an 80-year-old patient experiencing seizure activity, the recommended initial intramuscular (IM) dose of lorazepam is 0.05-0.1 mg/kg, with a maximum of 4 mg per dose. 1

Dosing Considerations for Elderly Patients

• The standard IM lorazepam dose for seizure activity is 0.2 mg/kg (maximum: 6 mg per dose), which may be repeated every 10-15 minutes if needed 2
• However, elderly patients (80 years old) require dose reduction due to:
  • Decreased drug metabolism
  • Increased sensitivity to benzodiazepines
  • Higher risk of respiratory depression
• Therefore, starting at the lower end of the dosing range (0.05-0.1 mg/kg) is prudent for geriatric patients 1

Administration and Monitoring

• Ensure proper IM administration technique (deep intramuscular injection)
• Monitor vital signs closely, with particular attention to:
  • Respiratory rate and oxygen saturation (risk of respiratory depression) 2, 1
  • Blood pressure (risk of hypotension)
  • Level of consciousness
• Be prepared to provide respiratory support if needed, as benzodiazepines can cause apnea, especially in elderly patients 1
• Consider having flumazenil available as a reversal agent for life-threatening respiratory depression, though be aware it will also reverse the anticonvulsant effects 1

Efficacy and Alternative Considerations

• Lorazepam has been shown to be more effective than phenytoin for overt generalized convulsive status epilepticus 3
• Underdosing of lorazepam has been associated with progression to refractory status epilepticus 4
• For elderly patients with multiple comorbidities or who are at high risk for respiratory depression, alternative agents such as intravenous levetiracetam may be considered, as it has shown efficacy and good tolerability in older patients 5

Common Pitfalls and Caveats

• Avoid underdosing: Studies show that underdosing lorazepam increases the risk of progression to refractory status epilepticus 4
• Beware of drug interactions: Elderly patients are often on multiple medications that may interact with lorazepam
• Monitor for paradoxical reactions: Though more common in younger patients, agitation can occasionally occur in elderly patients 6
• Prolonged monitoring is essential: The effects of lorazepam may be extended in elderly patients due to decreased clearance
• Consider comorbidities: Adjust dosing for patients with hepatic or renal impairment