What is an appropriate prn (pro re nata, or as needed) anti-anxiety medication in the geriatric population?

Appropriate PRN Anti-Anxiety Medication in the Geriatric Population

For PRN anti-anxiety management in geriatric patients, lorazepam 0.25-0.5 mg orally is the recommended first-line choice, with a maximum of 2 mg in 24 hours. 1

First-Line PRN Recommendation

Lorazepam is the preferred benzodiazepine for PRN use in elderly patients due to its short half-life, lack of active metabolites, and predictable pharmacokinetics. 2, 1

Specific Dosing

• Start with 0.25-0.5 mg orally PRN for anxiety without delirium 1
• Maximum daily dose: 2 mg in 24 hours 1
• For elderly or debilitated patients, the FDA label recommends an initial dosage of 1-2 mg/day in divided doses, adjusted as needed 3
• Use the lower end of the dosing range (0.25 mg) in frail patients or those with COPD 2, 1

Why Lorazepam Over Other Benzodiazepines

The evidence strongly favors short half-life benzodiazepines in the elderly, as long half-life agents cause cumulative toxicity. 2, 4 Among short-acting options (lorazepam, oxazepam, temazepam), lorazepam is specifically recommended for PRN anxiety management in multiple guidelines. 2, 1 While some older research suggests high-potency benzodiazepines like lorazepam may carry risks of dependence and memory impairment compared to oxazepam 4, the most recent 2025 guidelines from the American College of Emergency Physicians clearly endorse lorazepam as first-line for geriatric anxiety. 1

Alternative PRN Options When Lorazepam is Contraindicated

For Patients Unable to Swallow

• Midazolam 2.5 mg subcutaneously every 2-4 hours PRN 1
• Reduce to 5 mg over 24 hours if eGFR <30 mL/minute 1
• Use lower doses (0.5-1 mg) in frail patients or those with COPD 2

For Anxiety with Delirium or Agitation

Switch to haloperidol 0.5 mg orally PRN (not lorazepam), as benzodiazepines can worsen delirium. 1 Maximum daily dose is 5 mg in elderly patients. 1

Second-Line PRN Options

If benzodiazepines are ineffective or contraindicated:

• Quetiapine 25 mg orally PRN 1
• Risperidone 0.5 mg orally PRN (reduce dose in severe renal/hepatic impairment) 1
• Monitor closely for orthostatic hypotension, dizziness, and extrapyramidal side effects 2, 1

Critical Safety Considerations

Paradoxical Reactions and Cognitive Effects

• Approximately 10% of elderly patients experience paradoxical agitation with benzodiazepines 2
• Regular benzodiazepine use can lead to tolerance, addiction, depression, and cognitive impairment 2
• Infrequent, low doses of short half-life agents are least problematic 2

Fall Risk and Sedation

• Benzodiazepines significantly increase fall risk in the elderly 2
• Use lower doses when combining with antipsychotics to avoid oversedation 1
• Monitor for sedation and unsteadiness, which increase with age 3

When to Avoid Benzodiazepines Entirely

The 2024 Harvard algorithm recommends caution with benzodiazepines for acute treatment in older adults, favoring SSRIs (sertraline or escitalopram) for ongoing anxiety management. 5 However, for true PRN use in acute anxiety episodes without delirium, lorazepam remains appropriate at low doses. 1

Common Pitfalls to Avoid

• Do not use long half-life benzodiazepines (diazepam, chlordiazepoxide, flurazepam) due to accumulation and prolonged sedation 2, 4
• Do not combine benzodiazepines with high-dose olanzapine due to reported fatalities 2
• Do not use benzodiazepines as monotherapy for delirium-related agitation, as they may worsen confusion 2, 1
• Avoid abrupt discontinuation after regular use; taper gradually to prevent withdrawal reactions 3

Before Starting Any PRN Medication

Address reversible causes first:

• Explore patient concerns and ensure effective communication 1
• Treat physical causes: hypoxia, pain, constipation, urinary retention 1
• Review medication list for drugs causing anxiety (steroids, stimulants, caffeine) 1