Can Propranolol 20mg Tablets Be Split?
No, propranolol 20mg tablets should not be split for patients with swallowing difficulties due to significant dose variability and inaccuracy that poses safety risks. Instead, use a commercially available oral liquid formulation or have a pharmacy compound a suspension from tablets.
Evidence Against Tablet Splitting
Dose Uniformity Problems
- Manual splitting of propranolol 40mg tablets produced 42% of quarters with active drug content outside the acceptable ±10% range, with actual propranolol content ranging from 7.36-12.23 mg when 10 mg was expected 1
- Only 76.1% of split quarters were deemed adequate for administration, with significant weight variability (mean 49.56 ± 5.27 mg versus expected weight) 1
- Splitting caused unpredictable drug loss, with 55.88% of quarters weighing less than theoretical and others weighing more than expected 1
Clinical Significance
- This dose variability is particularly dangerous with propranolol given its narrow therapeutic index and serious adverse effects including hypotension, bradycardia, bronchospasm, and worsening heart failure 2, 3
- The American Heart Association emphasizes monitoring for hypotension and bradycardia even with accurate dosing 3, 4
Recommended Alternatives
Liquid Formulation (Preferred)
- A commercially available oral liquid formulation of propranolol (10 mg/mL) allows for accurate dose changes and is equally effective as tablets 5
- This liquid form has been successfully used in pediatric patients and is ideal for patients with swallowing difficulties 5
Compounded Suspension
- If commercial liquid is unavailable, pharmacies can compound a stable propranolol suspension from tablets at 1 mg/mL concentration 6
- This compounded suspension remains stable for at least 4 months when stored at room or refrigerated temperature 6
- The suspension maintains >90% of initial propranolol concentration throughout the storage period with no microbial growth 6
Critical Safety Considerations
Pre-Treatment Assessment Required
- Screen for absolute contraindications: second or third-degree heart block, decompensated heart failure, asthma/obstructive airway disease, cardiogenic shock, and hypotension 2, 3, 4
- Perform baseline cardiovascular examination with auscultation and measure heart rate and blood pressure 3, 4
Monitoring During Treatment
- Monitor for hypotension and bradycardia, especially during dose escalation 3, 4
- In diabetic patients, counsel that propranolol masks hypoglycemia symptoms 3, 4
Discontinuation Warning
- Never abruptly discontinue propranolol—taper gradually over several weeks to prevent rebound hypertension, tachycardia, or angina 3, 7, 4
Dosing Guidance for Liquid Formulation
Standard Adult Dosing
- For anxiety or palpitations: Start with 10-40 mg three to four times daily of immediate-release formulation, titrating based on symptom control 3, 4
- For hypertension: 80-160 mg daily divided into 2 doses 3
- Typical effective range is 80-160 mg daily in divided doses 3