What are good PRN (as needed) medications for anxiety, apart from propranolol (Inderal)?

PRN Anxiety Medications Beyond Propranolol

Lorazepam 0.5-1 mg orally every 4-6 hours as needed (maximum 4 mg/24 hours) is the first-line PRN medication for acute anxiety episodes. 1, 2

Primary Recommendation: Benzodiazepines

Lorazepam (Ativan) is the preferred benzodiazepine for PRN anxiety due to its intermediate half-life, rapid onset, complete absorption, lack of active metabolites, and predictable pharmacokinetics. 1, 2 This makes it ideal for as-needed dosing compared to longer-acting agents like diazepam or shorter-acting options like alprazolam.

Dosing Strategy

• Start with 0.5 mg orally every 4-6 hours as needed 1, 2
• Increase to 1 mg per dose if 0.5 mg is insufficient 1
• Maximum daily dose: 4 mg in 24 hours 1, 2
• For elderly patients: reduce to 0.25-0.5 mg per dose with maximum 2 mg/day 2

Alternative Benzodiazepine Options

Alprazolam is FDA-approved for generalized anxiety disorder and panic disorder, effective for both sustained anxiety and episodic panic attacks. 3 However, its shorter half-life may require more frequent dosing and carries higher risk of rebound anxiety between doses compared to lorazepam. 4

For patients unable to swallow oral medications, midazolam 2.5-5 mg subcutaneously every 2-4 hours as needed provides rapid relief with shorter duration of action. 1, 2

Critical Safety Precautions with Benzodiazepines

Benzodiazepines should be prescribed for short-term use only, as approximately half of patients prescribed benzodiazepines continue them for at least 12 months, which contradicts guideline recommendations. 2 Long-term continuous use carries significant risks of dependence and withdrawal. 1, 2

Absolute Contraindications and Warnings

• Never combine with opioids due to dangerous respiratory depression risk 1, 2
• Avoid alcohol and other CNS depressants 1
• Do not drive or operate machinery until effects are known 1

Monitoring Requirements

• Assess for signs of dependence or misuse at each follow-up 1, 2
• Evaluate treatment response and side effects regularly 2
• Consider cognitive behavioral therapy as adjunctive or alternative treatment for longer-term management 2

Non-Benzodiazepine Alternatives

Hydroxyzine (Antihistamine)

Hydroxyzine is a non-addictive alternative particularly useful when sedation is desired or in patients with substance abuse history. 2 However, antihistamines like diphenhydramine are less reliable for anxiety compared to benzodiazepines and may cause excessive drowsiness. 1

Buspirone

Buspirone may be considered for patients with substance abuse history or concerns about benzodiazepine dependence. 1 However, buspirone requires regular dosing (not truly PRN) and takes 2-4 weeks to become effective, making it unsuitable for acute anxiety relief. 5

Why Propranolol Has Limited Utility

Propranolol is most effective for somatic anxiety symptoms (palpitations, tremor, sweating) rather than psychic anxiety (worry, fear, apprehension). 6 Studies show propranolol is more effective than placebo only in patients with predominantly somatic anxiety complaints, not those with primarily psychological symptoms. 6

For generalized anxiety disorder, propranolol is less effective than benzodiazepines and should be reserved for patients with prominent cardiovascular symptoms when combined with benzodiazepines or in non-responders to conventional treatment. 7, 8 Propranolol has not shown efficacy in panic disorder and may induce depression, requiring caution in patients with concurrent depressive illness. 7

While one study found both propranolol and atenolol effective for generalized anxiety, 8 and combination therapy with diazepam showed some benefit, 9 the evidence does not support routine use of beta-blockers as monotherapy for anxiety disorders. 7

Clinical Implementation Algorithm

1. Prescribe lorazepam 0.5 mg tablets with instructions: take 0.5-1 mg every 4-6 hours as needed for anxiety, maximum 4 mg/24 hours 1

2. Patient education must include:

   • Take lowest effective dose 1
   • Use only when truly needed 1
   • Avoid alcohol and CNS depressants 1
   • No driving until effects are known 1

3. For patients on fluoxetine and prazosin specifically: lorazepam has no significant pharmacokinetic or pharmacodynamic interactions with fluoxetine, making it a safe combination. 1 Monitor for additive sedation when prazosin is taken at night, though this is typically well-tolerated. 1

4. If benzodiazepines are contraindicated: consider hydroxyzine for non-addictive alternative 2 or buspirone for patients requiring longer-term management without dependence risk. 1

5. Avoid antipsychotics for PRN anxiety in patients without psychosis due to risk of extrapyramidal symptoms and metabolic side effects. 1