Propranolol

A non-selective beta-blocker used in heart disease, anxiety, and migraine prevention.

What is Propranolol?

Propranolol is a non-selective beta-adrenergic blocker that blocks both β₁ and β₂ receptors. It is used in cardiovascular disorders and several non-cardiac conditions.

It reduces heart rate, blood pressure, and sympathetic nervous system activity.

History & Background

Propranolol was the first clinically successful beta-blocker and revolutionized the treatment of hypertension, angina, and arrhythmias.

Chemical Structure & Properties

• IUPAC name: 1-[(1-methylethyl)amino]-3-(1-naphthyloxy)propan-2-ol
• Molecular formula: C₁₆H₂₁NO₂
• Molar mass: 259.34 g/mol
• Functional groups: Secondary amine, alcohol, aromatic ring

Mechanism of Action

Propranolol produces its effects by:

• Blocking β₁ receptors → ↓ heart rate & contractility
• Blocking β₂ receptors → ↓ sympathetic activity
• Reducing cardiac output and blood pressure

Pharmacokinetics

• Absorption: Well absorbed orally
• First-pass metabolism: Extensive (liver)
• Peak plasma time: 1–2 hours
• Half-life: 3–6 hours
• Excretion: Urine (metabolites)

Medical Uses

• Hypertension
• Angina pectoris
• Arrhythmias
• Migraine prophylaxis
• Essential tremor
• Performance anxiety

Dosage Guidelines

Hypertension: 40–160 mg/day in divided doses

Migraine: 40–80 mg twice daily

⚠️ Do not stop abruptly – risk of rebound hypertension.

Side Effects

• Bradycardia
• Fatigue
• Cold extremities
• Sleep disturbances

Warnings & Precautions

• Contraindicated in asthma and COPD
• May mask hypoglycemia symptoms
• Use cautiously in heart failure

Drug Interactions

• Calcium channel blockers (verapamil)
• Insulin and antidiabetic drugs
• Alcohol

Frequently Asked Questions

Is propranolol selective? – No.

Does it help anxiety? – Yes.

Can asthmatics use it? – No.

Is it safe long-term? – Yes, with monitoring.

⚠️ Educational content only. Not a substitute for professional medical advice.