Propranolol

# Propranolol ## Overview Propranolol is a non-selective beta-blocker (beta-1 and beta-2 adrenergic antagonist). It is highly lipophilic, crosses the blood-brain barrier, and undergoes extensive first-pass hepatic metabolism. Available as immediate-release (IR) tablets, extended-release (ER) capsules, and oral solution. ## Primary Indications - Essential hypertension - Angina pectoris - Atrial fibrillation (rate control), supraventricular tachycardia - Migraine prophylaxis - Essential tremor - Infantile hemangioma (US FDA-approved indication) - Performance anxiety (off-label) - Thyrotoxicosis (adjunct) ## Adult Dosing **Hypertension/Angina:** Initial 40 mg twice daily (IR); max 640 mg/day in divided doses. ER: 80 mg once daily; max 640 mg/day. **Migraine prophylaxis:** 80–160 mg/day divided every 6–8 hours (IR) or 80–160 mg once daily (ER). **Tremor:** 40 mg twice daily; up to 240 mg/day. **Performance anxiety:** 10–40 mg taken 1–2 hours before event (off-label). **Rate control (AF):** 10–40 mg three to four times daily; titrate. ## Pediatric Dosing *Dosing varies by indication and local protocol. Verify specific guidance.* **Infantile hemangioma:** Approved oral solution (Hemangeol™). Dose: 3–4 mg/kg/day total, divided every 6–8 hours. Typical starting dose 1 mg/kg/day, titrated over 2 weeks. Max 5 mg/kg/day. **Arrhythmia / Hypertension:** 0.5–1 mg/kg/day divided every 6–8 hours; max 16 mg/kg/day (higher doses used by specialists). Do not exceed adult maximum. **Migraine prophylaxis:** 0.5–1 mg/kg/day divided twice or three times daily; max 4 mg/kg/day. ## Dose Adjustments **Hepatic impairment:** Reduce dose; monitor for toxicity. **Renal impairment:** No standard adjustment required; use caution if GFR <30 mL/min. **Elderly:** Start at low end of dose range; titrate slowly. ## Contraindications - Bronchial asthma or COPD with bronchospasm - Cardiogenic shock - Severe sinus bradycardia or sick sinus syndrome (without pacemaker) - Heart block (second/third degree) - Uncompensated heart failure - Pheochromocytoma (without alpha-blocker pre-treatment) - Hypersensitivity to propranolol ## Adverse Effects - Bradycardia, hypotension, heart block - Fatigue, dizziness, depression (lipophilic) - Bronchospasm (avoid in asthma) - Cold extremities, Raynaud phenomenon - GI upset, constipation - Masking of hypoglycemia or hyperthyroidism symptoms - Rebound hypertension or tachycardia with abrupt discontinuation ## Key Drug Interactions - **Calcium channel blockers (verapamil/diltiazem):** additive bradycardia/AV block - **Digoxin:** bradycardia risk - **CYP1A2 inhibitors (e.g., cimetidine, fluvoxamine):** increase propranolol levels - **CYP1A2 inducers (e.g., smoking, rifampin):** decrease efficacy - **Insulin/sulfonylureas:** masks hypoglycemia symptoms (e.g., tachycardia) - **NSAIDs:** reduce antihypertensive effect ## Monitoring - Heart rate, blood pressure, ECG if indicated at baseline and during titration - Signs of bronchospasm or heart failure - Mental status changes (depression, sleep disturbance) - Glucose monitoring in diabetics (symptoms of hypoglycemia masked) ## Clinical Pearls - Do not discontinue abruptly after chronic use – taper over 1–2 weeks to avoid rebound angina, hypertension, or MI. - Use with caution in patients with peripheral vascular disease. - Absorption is increased with food; take consistently. - For infantile hemangioma: monitor for bradycardia, hypoglycemia, and sleep disturbances. - ER formulations should not be substituted IR on a mg-to-mg basis. --- **Educational Disclaimer:** This information is for educational purposes and does not replace clinical judgment. Always verify dosing against current approved prescribing information (e.g., FDA, EMA, local formulary) for your specific patient population and indication.