What is the starting dose of propranolol (PRN) for anxiety?

Propranolol PRN for Anxiety: Starting Dose

For situational/performance anxiety with prominent somatic symptoms (tremor, palpitations, sweating), start with propranolol 10-40 mg taken 30-60 minutes before the anxiety-provoking event, with 20 mg being the optimal balance of efficacy and minimal side effects. 1, 2

Patient Selection: Who Benefits Most

Propranolol is specifically effective for patients whose anxiety manifests primarily as physical/autonomic symptoms rather than psychological worry 1, 3:

• Ideal candidates: Tremor, palpitations, tachycardia, sweating, and other somatic manifestations 1
• Poor candidates: Predominantly psychological symptoms (worry, rumination) without prominent physical symptoms 3
• Best use case: Performance anxiety and specific situational triggers, NOT chronic generalized anxiety 1, 4

The evidence shows propranolol was more effective than placebo in patients with somatic anxiety but showed no benefit in those with primarily psychic anxiety 3. This is critical for appropriate patient selection.

PRN Dosing Protocol

Single-Dose Situational Use

• Starting dose: 10-20 mg taken 30-60 minutes before the anticipated stressor 1, 2
• Alternative dose: 20-40 mg if 10-20 mg proves insufficient 1, 4
• Maximum single PRN dose: 40 mg 1
• Timing: Effects begin within 1-2 hours and are mediated by peripheral beta-receptor blockade 4

A rigorous double-blind study demonstrated that 20 mg propranolol provided significant anxiety reduction with minimal side effects compared to 40 mg, which caused bradycardia in 25% and hypotension in 10% of patients 2. This makes 20 mg the optimal starting dose for most patients 2.

If Chronic Dosing Becomes Necessary

While PRN use is preferred, if regular dosing is required 4, 5:

• Initial: 40 mg daily (divided into 2 doses or single dose with long-acting formulation) 1
• Maintenance: 80-160 mg daily in divided doses 1, 4
• Maximum: 320 mg daily for standard anxiety treatment 5

Higher doses (160 mg/day) may improve other anxiety symptoms after several weeks of treatment, but this requires longer-term use 4.

Mandatory Pre-Treatment Assessment

Before prescribing propranolol, screen for absolute contraindications 1, 6:

• Second or third-degree heart block (absolute contraindication) 1, 6
• Decompensated heart failure 1, 6
• Asthma or obstructive airway disease 1, 6
• Cardiogenic shock 1
• Sinus node dysfunction without pacemaker 1

Baseline Assessment Required

• Heart rate and blood pressure measurement 1, 6
• Cardiovascular examination with auscultation 1
• Screen for history of bronchospasm, diabetes, hypoglycemia 1, 6
• Review concurrent medications affecting cardiac conduction 1

Important: Routine blood work (CBC, renal, liver, thyroid function), ECG, and echocardiogram are NOT required in otherwise healthy adults 1. These are only needed if cardiac concerns exist 1.

Critical Safety Warnings

Hypoglycemia Risk

Propranolol masks symptoms of hypoglycemia in diabetic patients 7, 1. Use with extreme caution in patients with diabetes or history of hypoglycemic episodes 1.

Discontinuation Protocol

Never abruptly discontinue propranolol after chronic use 1, 6. This can precipitate:

• Rebound hypertension 1
• Rebound tachycardia 1, 6
• Angina 1

If discontinuation is needed after regular use, taper gradually over several weeks 1, 6.

Drug Interactions

Avoid combining with non-dihydropyridine calcium channel blockers (diltiazem, verapamil) due to increased risk of severe bradycardia and heart block 1.

Common Pitfalls to Avoid

1. Using propranolol for psychological anxiety without somatic symptoms - This is ineffective and wastes resources 3
2. Starting with doses >40 mg for PRN use - This increases side effects without additional benefit 2
3. Prescribing for chronic generalized anxiety as first-line - Propranolol is deprecated for this indication; it's for situational use 1
4. Failing to screen for asthma/COPD - This can precipitate life-threatening bronchospasm 1, 6
5. Combining with other cardiac conduction-slowing drugs without careful monitoring 1

Monitoring Requirements

For PRN use, no routine monitoring is required between doses if the patient remains asymptomatic 1. However, patients should be counseled to report:

• Dizziness or lightheadedness (hypotension) 1
• Excessive fatigue 1
• Shortness of breath or wheezing 1
• Cold extremities 1