What is the typical dosage and usage of Propranolol (beta-blocker) for treating hypertension, angina, and arrhythmias?

Propranolol Dosing for Hypertension, Angina, and Arrhythmias

For hypertension, start with propranolol extended-release 80 mg once daily and titrate to 120-160 mg daily for maintenance, with a maximum of 640 mg daily if needed; for angina, begin at 80 mg once daily and increase gradually to an average optimal dose of 160 mg daily (maximum 320 mg daily); for arrhythmias, use immediate-release formulation at 80-160 mg daily in divided doses. 1

Hypertension Management

Initial Dosing Strategy

• Begin with propranolol extended-release 80 mg once daily, whether used alone or combined with a diuretic 1
• The usual maintenance dosage is 120-160 mg once daily, though some patients may require up to 640 mg daily for adequate blood pressure control 1
• Full hypertensive response to a given dosage is variable and may range from a few days to several weeks 1

Important Formulation Considerations

• Extended-release capsules are not a simple mg-for-mg substitute for immediate-release tablets due to different kinetics and lower blood levels 1
• Extended-release formulations have a prolonged terminal half-life of 8-11 hours compared to immediate-release, allowing once-daily dosing 2
• Systemic bioavailability of extended-release propranolol is 30-50% less than conventional formulation, requiring retitration when switching 1, 2

Angina Pectoris Management

Dosing Protocol

• Start with 80 mg extended-release once daily and increase gradually at 3-7 day intervals until optimal response is obtained 1
• The average optimal dosage is 160 mg once daily, though individual patients may respond at any dosage level 1
• The value and safety of dosages exceeding 320 mg per day have not been established for angina 1

Evidence for Higher Dosing in Severe Angina

• For severe angina (NYHA class III or IV), the average optimum dosage may be 500-800 mg daily when using immediate-release formulations, similar to or higher than doses used for hypertension 3
• A dose-response study demonstrated progressive reduction in angina attacks with logarithmic increases up to an average of 417 mg daily 3
• Dosage should be adjusted to produce a resting heart rate of 55-60 beats per minute unless prevented by side effects 3

Long-Term Efficacy

• Long-term therapy (5-8 years) with a mean daily dose of 255 mg showed 32% of patients per year were angina-free, and 84% per year had 50% or more reduction in anginal episodes 4
• No evidence of tachyphylaxis was found with long-term propranolol therapy 4
• Patients with 50% or greater reduction in anginal pain had a nearly four-fold lower mortality rate compared to those with less than 50% reduction 4

Arrhythmia Management

Dosing for Supraventricular Arrhythmias

• Use immediate-release formulation at 80-160 mg daily in divided doses (typically twice daily) 5
• For acute situations, intravenous propranolol may be considered, though specific IV dosing protocols are not detailed in the propranolol-specific evidence provided

Critical Pre-Treatment Assessment

Absolute Contraindications

• Second or third-degree heart block 5
• Decompensated heart failure 5
• Asthma or obstructive airway disease 5
• Cardiogenic shock 5
• Sinus node dysfunction without a pacemaker 5

Baseline Evaluation

• Measure heart rate and blood pressure 5
• Perform cardiovascular examination with auscultation 5
• Screen for history of bronchospasm, diabetes, and concurrent medications affecting cardiac conduction 5
• ECG and echocardiogram are only needed in selected cases with cardiac concerns, not routinely required in otherwise healthy adults 5

Safety Considerations and Monitoring

Initiation Strategy

• The greatest danger of precipitating heart failure occurs at treatment initiation, even with small starting doses 3
• Once treatment has begun, even a 25% dose increase represents a small pharmacological increment with lower risk 3
• Patients with cardiothoracic ratio greater than 0.5 are at high risk for heart failure during the first 3 years of therapy 4

Ongoing Monitoring

• No routine vital sign monitoring is required between appointments if the patient is stable and asymptomatic 5
• Monitor for hypotension and bradycardia, especially during dose escalation 5
• Watch for worsening heart failure, bronchospasm, and severe bradycardia 5
• In diabetic patients, propranolol masks symptoms of hypoglycemia and should be used with extreme caution 5

Discontinuation Protocol

• Never abruptly discontinue propranolol, especially after chronic use 5, 1
• Taper gradually over several weeks to prevent rebound hypertension, tachycardia, or worsening angina 5, 1
• For angina patients, reduce dosage gradually over a few weeks when discontinuing 1

Drug Interactions to Avoid

• Avoid routine combination with non-dihydropyridine calcium channel blockers (diltiazem, verapamil) due to increased risk of bradycardia and heart block 5
• Use caution with other medications that affect cardiac conduction 5

Common Pitfalls

• Failing to recognize that extended-release and immediate-release formulations are not interchangeable on a mg-for-mg basis 1
• Starting with excessively high doses in patients at risk for heart failure 3, 4
• Abruptly discontinuing therapy, which can precipitate serious cardiovascular events 5, 1
• Using propranolol in patients with relative contraindications such as previous heart failure history or cardiothoracic ratio >0.5 4