Introduction:
Non-selective beta-blockers block both β₁ and β₂ adrenergic receptors, affecting the heart, lungs, and blood vessels.
They reduce heart rate, myocardial contractility, and cardiac output, lowering blood pressure and oxygen demand.
By blocking β₂ receptors, they may cause bronchoconstriction and vasoconstriction.
They are used in hypertension, angina, arrhythmias, migraine prophylaxis, and portal hypertension.
Examples include propranolol, nadolol, and timolol.
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| Rx Insights: Non-Selective Beta Blockers |
💊 Drug Class:
β₁ + β₂ adrenergic receptor antagonists.
🧬 Mechanism of Action:
β₁ blockade (heart): ↓ HR, ↓ contractility, ↓ renin release.
β₂ blockade (lungs, vessels, liver): bronchoconstriction, vasoconstriction, ↓ glycogenolysis.
💊 Common Drugs:
Propranolol.
Nadolol.
Timolol.
Sotalol (also class III antiarrhythmic).
✅ Indications:
Hypertension.
Angina, arrhythmias.
Post-MI secondary prevention.
Migraine prophylaxis (propranolol).
Thyrotoxicosis (symptom control).
Glaucoma (timolol eye drops).
⚠️ Side Effects:
Bradycardia, hypotension.
Bronchospasm (dangerous in asthma/COPD).
Fatigue, depression.
Cold extremities, Raynaud’s phenomenon.
Masked hypoglycemia symptoms in diabetics.
🚫 Contraindications:
Asthma & COPD.
Severe bradycardia, AV block, sick sinus syndrome.
Uncontrolled heart failure.
Severe peripheral vascular disease.
🔍 Monitoring:
HR & BP.
Respiratory status (wheezing, bronchospasm risk).
Glucose control in diabetics.
Adherence (risk if stopped abruptly).
💊 Major Drug Interactions:
1. Verapamil / Diltiazem → ↑ risk of bradycardia & AV block.
2. Insulin & oral hypoglycemics → mask hypoglycemia symptoms.
3. NSAIDs → ↓ antihypertensive efficacy.
💡 Clinical Tips:
Avoid in patients with asthma/COPD – risk of bronchospasm.
Propranolol useful in migraine, portal. hypertension, thyrotoxicosis.
Timolol eye drops effective for glaucoma.
Taper gradually to avoid rebound angina or arrhythmias.
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