What is the recommended dosing for propranolol (beta-blocker) in managing anxiety and sinus tachycardia?

Propranolol Dosing for Anxiety and Sinus Tachycardia

For anxiety with prominent somatic symptoms (tremor, palpitations), propranolol 40 mg daily is effective within 1-2 hours, while more severe or generalized anxiety requires 80-320 mg daily in divided doses, titrated to achieve virtual abolition of orthostatic and hyperventilatory tachycardia. 1, 2

Anxiety Management

Acute Situational Anxiety (Performance Anxiety)

• Start with 40 mg orally as a single dose, taken 1-2 hours before the anxiety-provoking event 2
• This low dose effectively blocks peripheral beta-receptors, reducing tremor and palpitations 2
• Response occurs within 1-2 hours of administration 2

Chronic Anxiety Disorders

• Initial dose: 80 mg daily in divided doses (typically 40 mg twice daily) 1
• Titrate upward based on clinical response and degree of beta-blockade achieved 1
• Target endpoint: virtual abolition of orthostatic tachycardia and hyperventilatory tachycardia 1
• Usual effective range: 80-320 mg daily in divided doses 1
• Some patients with intense symptoms may temporarily require up to 1200 mg daily, though this is uncommon 1

Clinical Response Pattern

• Somatic symptoms (tremor, palpitations, sweating) respond most rapidly and reliably 2
• Psychic anxiety symptoms improve with higher doses (160 mg/day) after several weeks of treatment 2
• Depression, present in 50% of anxiety patients, usually improves but may persist as an isolated symptom requiring antidepressants 1
• Propranolol requirements typically diminish over time, with lasting remissions occurring frequently 1

Sinus Tachycardia Management

Physiological/Stress-Related Sinus Tachycardia

• Beta-blockade is extremely useful and effective for symptomatic sinus tachycardia triggered by emotional stress and anxiety-related disorders 3
• Dosing follows the same principles as anxiety management above 3

Inappropriate Sinus Tachycardia

• This condition predominantly affects women (90%), with mean age 38 years 3
• Symptoms include palpitations, chest pain, shortness of breath, dizziness, and presyncope 3
• Treatment requires identifying and addressing the underlying cause first 3
• Beta-blockade provides symptomatic relief when no reversible cause is identified 3

Intravenous Propranolol for Acute Sinus Tachycardia

• Dose: 1-3 mg IV administered slowly 4
• In neurosurgical patients with sinus tachycardia, an average dose of 2.05 mg reduced heart rate by 28 beats/min 4
• Critical monitoring required: heart rate and blood pressure response 4
• Effect is less pronounced when repeated within 90 minutes 4

Critical Contraindications and Precautions

Absolute Contraindications

• Sinus bradycardia 3
• Hypotension 3
• Greater than first-degree heart block 3
• Heart failure or cardiogenic shock 3
• Reactive airways disease or bronchial asthma 3
• Known hypersensitivity to propranolol 3

Special Populations Requiring Caution

Patients with Sinus Node Dysfunction:

• Propranolol increased spontaneous sinus cycle length by 17.4% in patients with sinus node dysfunction 5
• May cause marked bradyarrhythmias and precipitate second-degree SA block 5
• Increased sinoatrial conduction time from 179 to 213 msec 5
• Use with extreme caution or avoid entirely in patients with known sinus node disease 5

Patients on Concurrent Medications:

• Halothane potentiates heart rate reduction with propranolol 4
• Prior digitalization reduces propranolol's hypotensive effect but does not modify heart rate response 4

Monitoring Parameters

During Titration

• Assess orthostatic tachycardia response (measure heart rate supine and standing) 1
• Assess hyperventilatory tachycardia response (measure heart rate before and after hyperventilation) 1
• Target: virtual abolition of these tachycardic responses 1
• Monitor blood pressure at each visit, as propranolol may cause variable effects on blood pressure 4

Ongoing Monitoring

• Assess symptom relief (tremor, palpitations, psychic anxiety) 1, 2
• Monitor for depression, which may emerge or persist despite anxiety improvement 1
• Evaluate for bradycardia or hypotension, particularly in patients with underlying cardiac conduction abnormalities 5

Common Pitfalls to Avoid

• Do not use propranolol as first-line for panic attacks with severe shaking - it is more effective for mild-to-moderate somatic symptoms 2
• Do not assume all anxiety will respond to low doses - generalized anxiety often requires higher doses (160 mg/day) and several weeks of treatment 2
• Do not abruptly discontinue after long-term use - taper gradually over several weeks 6
• Do not use in patients with sinus node dysfunction without careful consideration - risk of severe bradyarrhythmias 5
• Do not repeat IV doses within 90 minutes expecting the same effect - tachyphylaxis occurs rapidly 4