What is a suitable PRN (as needed) option for an 83-year-old female patient with agitation who is already taking Ativan (lorazepam) 1 mg orally twice a day?

PRN Option for Agitation in an 83-Year-Old Female on Scheduled Lorazepam

For an 83-year-old female patient with agitation who is already taking Ativan (lorazepam) 1 mg PO BID, the most appropriate PRN option is low-dose haloperidol 0.5 mg orally every 2-4 hours as needed, with a maximum of 5 mg daily. 1

Medication Selection Algorithm

First-Line Option: Low-Dose Antipsychotic

• Haloperidol 0.5 mg PO every 2-4 hours PRN for agitation 1
  • Maximum daily dose: 5 mg in elderly patients 1
  • Advantages: Effective for acute agitation, doesn't add to benzodiazepine burden
  • Monitor for: Extrapyramidal symptoms, QTc prolongation

Alternative Options (if haloperidol is contraindicated):

1. Quetiapine 25-50 mg PO PRN (if patient has Parkinson's disease or is at high risk for EPS) 1, 2
2. Risperidone 0.25-0.5 mg PO PRN (reduced dose for elderly) 1

Rationale for Recommendation

1. Avoid additional benzodiazepines: The patient is already receiving scheduled lorazepam 1 mg PO BID. Adding PRN lorazepam increases the risk of:

   • Falls (especially concerning in an 83-year-old)
   • Paradoxical agitation
   • Excessive sedation
   • Delirium
   • Respiratory depression 1

2. Low-dose antipsychotics are preferred: For elderly patients with agitation, low-dose haloperidol is recommended as first-line PRN therapy when a patient is already on scheduled benzodiazepines 1.

3. Evidence supports low doses: Recent research indicates that low-dose haloperidol (≤0.5 mg) is as effective as higher doses for managing agitation in elderly patients, with fewer adverse effects 3. A retrospective study found no evidence that higher doses were more effective in decreasing duration of agitation or length of hospital stay 4.

Important Monitoring and Precautions

• Start at lowest effective dose: Begin with 0.5 mg haloperidol and only increase if necessary 3
• Monitor for extrapyramidal symptoms: Tremor, rigidity, akathisia
• Assess QTc interval: Obtain baseline ECG if possible
• Evaluate for reversible causes of agitation: Delirium, pain, constipation, urinary retention 1
• Implement non-pharmacological approaches concurrently:
  • Ensure adequate lighting
  • Provide orientation
  • Address underlying concerns
  • Maintain consistent caregivers 1

Special Considerations

• If the patient has Parkinson's disease, quetiapine would be preferred over haloperidol 2
• If the patient has a history of QTc prolongation, avoid haloperidol and consider risperidone at reduced doses 1
• For patients with severe hepatic or renal impairment, dose reduction is necessary 1
• Document specific target behaviors for PRN administration to ensure appropriate use 5

This approach minimizes the risk of adverse effects while providing effective management of agitation in this elderly patient who is already receiving scheduled benzodiazepine therapy.