Propranolol Dosing and Usage for Hypertension, Angina, and Arrhythmias
Propranolol is a non-selective beta-blocker with established dosing regimens for hypertension (80-160 mg daily), angina (160-320 mg daily), and arrhythmias (0.5-1 mg IV for acute treatment). 1
Hypertension Management
- Initial dosing: Start with 80 mg of propranolol extended-release capsules once daily, either alone or added to a diuretic 1
- Titration: Increase to 120 mg once daily or higher until adequate blood pressure control is achieved 1
- Maintenance dosing: Typical maintenance dose is 120-160 mg once daily, though some patients may require up to 640 mg daily 1
- Response time: Full hypertensive response may take several days to weeks at a given dosage 1
- Efficacy: When combined with a thiazide diuretic, propranolol (up to 480 mg/day) has been found effective in over 80% of patients with mild to moderately severe hypertension 2
Angina Pectoris Treatment
- Initial dosing: Begin with 80 mg propranolol extended-release capsules once daily 1
- Titration: Gradually increase dosage at three to seven-day intervals until optimal response is obtained 1
- Optimal dosage: Average optimal dosage appears to be 160 mg once daily, though individual responses may vary 1
- Maximum dosage: Safety and efficacy of doses exceeding 320 mg per day for angina have not been established 1
- Conventional vs. extended-release: Extended-release propranolol 160 mg daily has been shown to be as effective as conventional propranolol 40 mg four times daily for controlling angina 1
- Discontinuation: If treatment is to be discontinued, reduce dosage gradually over a period of a few weeks to avoid rebound effects 1
- Long-term efficacy: Studies show 84% of patients per year had 50% or more reduction in anginal episodes with propranolol, with no evidence of tachyphylaxis 3
Arrhythmia Management
- Acute IV administration: 0.5-1 mg IV over 1 minute, repeated up to a total dose of 0.1 mg/kg as needed 4
- Potential adverse effects: Hypotension, worsening heart failure, bronchospasm, bradycardia 4
- Contraindications: AV block greater than first degree or SA node dysfunction (in absence of pacemaker), cardiogenic shock, reactive airway disease, decompensated heart failure, hypotension 4
Special Considerations
- Extended-release formulation: Propranolol extended-release capsules are not a simple mg-for-mg substitute for conventional tablets; retitration may be necessary 1
- Pharmacokinetics: Extended-release propranolol has a prolonged terminal half-life (8-11 hours) compared to conventional formulation, with 30-50% less systemic bioavailability 5
- Monitoring parameters: Heart rate, blood pressure, signs of bronchospasm, and symptoms of heart failure 4, 1
- Common pitfalls:
- Abrupt discontinuation can lead to rebound tachycardia or exacerbation of ischemic heart disease 6
- Risk of cardiogenic shock in patients experiencing acute myocardial infarction while on propranolol 3
- Patients with cardiothoracic ratio >0.5 are at higher risk of developing heart failure during propranolol therapy 3
Contraindications and Precautions
- Absolute contraindications: Asthma, obstructive airway disease, decompensated heart failure, and pre-excited atrial fibrillation or flutter 4
- Relative contraindications: Previous history of congestive heart failure, cardiothoracic ratio >0.5 without overt heart failure, mild asthma 3
- Drug interactions: Propranolol can interact with calcium channel blockers, migraine drugs, theophylline, benzodiazepines, neuroleptic drugs, anti-ulcer drugs, and lipid-lowering drugs 1
Comparative Efficacy
- Beta-blockers: In comparative trials, propranolol has shown greater anti-anginal action than other beta-blockers like practolol and sotalol 7
- Dosing frequency: Once-daily extended-release propranolol is as effective as divided doses of conventional propranolol for treating hypertension and angina pectoris 5
Remember that propranolol is a non-selective beta-blocker that requires careful monitoring, especially when initiating therapy, and should be discontinued gradually to avoid rebound effects.