Propranolol Dosing Frequency
Propranolol immediate-release formulation requires dosing 2-4 times daily, while the long-acting (extended-release) formulation is dosed once daily. 1
Immediate-Release Formulation
The standard immediate-release propranolol requires multiple daily doses due to its short half-life:
- Oral immediate-release half-life: 3-6 hours 1
- Typical dosing frequency: 3-4 times daily for most indications 1, 2
- Alternative: Twice daily dosing is acceptable for certain indications like hypertension 1
Indication-Specific Immediate-Release Dosing:
- Atrial fibrillation rate control: 10-40 mg, 3-4 times daily 1
- Hypertension: 80-160 mg daily divided into 2 doses (twice daily) 1
- Palpitations/tachyarrhythmias: 10-40 mg three to four times daily 2
- Situational anxiety: Single dose of 10-20 mg taken 30-60 minutes before the anxiety-provoking event 3
Extended-Release (Long-Acting) Formulation
The extended-release formulation allows for simplified dosing:
- Extended-release half-life: 8-20 hours 1
- Dosing frequency: Once daily 1, 4
- Typical starting dose: 80 mg once daily 4
- Maintenance range: 120-160 mg once daily for most indications 4
The extended-release formulation maintains therapeutic plasma concentrations throughout a 24-hour period, providing sustained beta-blockade with improved compliance potential. 5
Critical Dosing Considerations
Bioavailability Differences:
Extended-release propranolol is NOT a simple mg-for-mg substitute for immediate-release. 4 The extended-release formulation has 30-50% lower systemic bioavailability compared to immediate-release, requiring retitration when switching between formulations. 5
Intravenous Administration:
For acute settings requiring rapid effect:
- IV dose: 1 mg over 1 minute 1
- May repeat every 2 minutes as needed, up to 3 doses 1, 2
- IV half-life: 2.4 hours 1
Important Safety Warnings
Discontinuation Protocol:
Never abruptly discontinue propranolol after chronic use. 3, 2 Abrupt withdrawal can precipitate rebound hypertension, tachycardia, or angina. 3, 2 Taper gradually over 1-3 weeks when discontinuing. 3, 6
A prolonged small-dose tapering schedule (reducing to 30 mg daily for 2 weeks before complete withdrawal) prevents enhanced cardiac beta-adrenergic sensitivity and adverse withdrawal events more effectively than rapid dose reduction. 6
Monitoring Requirements:
- Monitor for hypotension and bradycardia, especially during dose escalation 3, 2
- Baseline cardiovascular assessment including heart rate, blood pressure, and auscultation is mandatory before initiation 3, 2
- No routine vital sign monitoring required between appointments if patient is stable and asymptomatic 3
Absolute Contraindications:
- Second or third-degree heart block 3, 2
- Decompensated heart failure 3, 2
- Asthma or obstructive airway disease 3, 7
- Cardiogenic shock 2
- Sinus node dysfunction without pacemaker 3
Drug Interactions:
Avoid routine combination with non-dihydropyridine calcium channel blockers (diltiazem, verapamil) due to increased risk of severe bradycardia and heart block. 3, 2
Special Populations
Elderly Patients:
Lower doses may be required due to altered pharmacokinetics and increased sensitivity to beta-blockers. 3, 7
Diabetic Patients:
Propranolol masks symptoms of hypoglycemia—counsel patients accordingly and use with extreme caution in those with history of hypoglycemic episodes. 3, 2