What is a reasonable PRN medication option to calm acute anxiety episodes in a 70-year-old female patient with Parkinson's disease, preferring to avoid benzodiazepines, between Buspar (buspirone) and Trazodone (trazodone)?

PRN Medication for Acute Anxiety in Parkinson's Disease: Neither Buspar nor Trazodone is Ideal

For acute anxiety episodes requiring PRN relief in a 70-year-old female with Parkinson's disease, neither buspirone (Buspar) nor trazodone is appropriate—buspirone is not effective for acute/PRN use and worsens motor symptoms in PD, while trazodone lacks evidence for acute anxiety management in this population. If you must avoid benzodiazepines entirely, consider low-dose quetiapine 25mg PRN as a second-line option, though this is off-label and requires careful monitoring for orthostatic hypotension 1.

Why Buspirone (Buspar) is Not Appropriate

Buspirone is fundamentally unsuitable for PRN use in any patient population:

• Buspirone requires 2-4 weeks of continuous daily dosing to achieve anxiolytic effects—it has no acute or immediate anxiety-relieving properties, making it useless as a PRN medication 2
• The medication is designed for chronic generalized anxiety disorder with gradual onset of benefit, not for episodic acute anxiety episodes 2

Buspirone specifically worsens Parkinson's disease symptoms:

• In controlled trials of PD patients, buspirone at high doses (100mg/day) significantly worsened disability ratings and increased anxiety scores 3
• A 2020 randomized trial in PD patients found that 41% failed to complete the study on buspirone, with 53% experiencing adverse events consistent with worsened motor function 4
• Even at conventional anxiolytic doses (10-40mg/day), buspirone showed no therapeutic benefit in PD patients 3, 5
• The mechanism involves dose-dependent stimulation of noradrenergic neurons in the locus ceruleus, which adversely affects parkinsonian symptoms 3

Why Trazodone is Not Appropriate

No evidence supports trazodone for acute PRN anxiety management in any population, let alone in Parkinson's disease. The provided guidelines and research do not address trazodone for this indication, suggesting lack of established efficacy or safety data for this specific use.

The Benzodiazepine Reality in Elderly PD Patients

Despite your preference to avoid benzodiazepines, they remain the evidence-based first-line PRN option for acute anxiety in elderly patients:

• Lorazepam 0.25-0.5mg orally PRN (maximum 2mg/24 hours) is specifically recommended for elderly patients with anxiety, including those with comorbid conditions 6, 1
• Lorazepam is preferred in geriatric populations due to its short half-life, lack of active metabolites, and predictable pharmacokinetics 1
• For this 70-year-old patient, start at the lower end: 0.25mg PRN every 4-6 hours as needed, maximum 2mg in 24 hours 6, 1

Critical safety considerations when using lorazepam in this patient:

• Approximately 10% of elderly patients experience paradoxical agitation with benzodiazepines 6, 1
• Significantly increased fall risk—counsel patient and caregivers explicitly 1
• Monitor for cognitive decline with regular use 6
• Avoid combining with other sedatives due to respiratory depression risk 6
• Use the lowest effective dose for the shortest duration possible 6

Alternative Second-Line PRN Option

If benzodiazepines are absolutely contraindicated:

• Quetiapine 25mg orally PRN can be considered as a second-line option for acute anxiety in elderly patients 1
• This is off-label use and requires careful monitoring for orthostatic hypotension and dizziness 1
• Start with 25mg and assess response after 30-60 minutes 1

Critical Clinical Pitfalls to Avoid

Before prescribing any PRN anxiolytic, address reversible causes:

• Explore patient concerns and ensure effective communication about PD symptoms 1
• Treat physical causes: hypoxia, pain, constipation, urinary retention 1
• Review current PD medications for anxiety-inducing effects (dopamine agonists can cause anxiety)
• Assess for undertreated motor symptoms that may be triggering anxiety episodes

Do not prescribe buspirone thinking it can be used "as needed"—this reflects a fundamental misunderstanding of its pharmacology 2. If chronic anxiety management is needed (not acute PRN), buspirone could be considered as a standing daily medication at 5-30mg/day divided doses, though efficacy in PD is questionable 7, 4.