Propranolol is a non-selective beta-adrenergic blocking agent, representing a cornerstone in the therapeutic management of a spectrum of cardiovascular and neurological conditions. As a first-generation beta-blocker, it exerts its pharmacological effects by competitively inhibiting catecholamine binding at both β₁- and β₂-adrenergic receptors. This comprehensive antagonism translates into a reduction in heart rate, myocardial contractility, and blood pressure, while also decreasing myocardial oxygen demand. Its utility extends beyond cardiology into neurology and psychiatry, primarily for the prophylaxis of migraine headaches and the symptomatic control of situational anxiety, making it a versatile agent in a specialist’s arsenal. This product card provides a detailed, evidence-based overview for healthcare professionals.

Features

• Pharmacological Class: Non-selective beta-adrenergic receptor antagonist (beta-blocker).
• Chemical Name: 1-(Isopropylamino)-3-(1-naphthyloxy)-2-propanol.
• Available Formulations: Immediate-release tablets (10 mg, 20 mg, 40 mg, 60 mg, 80 mg) and extended-release capsules (60 mg, 80 mg, 120 mg, 160 mg). Also available as an injectable solution for hospital use.
• Mechanism of Action: Competitively blocks both β₁-adrenergic receptors (in the heart) and β₂-adrenergic receptors (in the bronchial and vascular smooth muscles).
• Bioavailability: Approximately 25% due to significant first-pass metabolism in the liver.
• Half-life: 3 to 6 hours for the immediate-release formulation; the extended-release formulation is designed for once-daily dosing.
• Metabolism: Primarily hepatic via the CYP2D6 enzyme pathway (subject to genetic polymorphism).
• Excretion: Mainly renal as metabolites.

Benefits

• Provides effective control of hypertension by reducing cardiac output and peripheral vascular resistance.
• Decreases the frequency and severity of angina pectoris attacks by lowering myocardial oxygen consumption.
• Reduces mortality and the risk of reinfarction in post-myocardial infarction patients.
• Offers prophylactic management for migraine headaches, reducing their frequency and intensity.
• Mitigates the somatic symptoms of performance and situational anxiety (e.g., tremor, tachycardia).
• Can manage symptoms of hyperthyroidism, such as tachycardia and tremor, while awaiting definitive treatment.

Common use

Propranolol is indicated for the management of hypertension, either as monotherapy or in combination with other antihypertensive agents. It is a fundamental treatment for angina pectoris, helping to prevent ischemic episodes. It is a standard of care for the secondary prevention of mortality after a myocardial infarction. In neurological practice, it is a first-line prophylactic treatment for migraine. Off-label, it is widely used to address the physical manifestations of anxiety (e.g., essential tremor, stage fright) and to manage symptomatic tachycardia in hyperthyroidism.

Dosage and direction

Dosage is highly individualized and must be titrated based on the patient’s condition and response. This is a general guide; always follow specific prescribing instructions.

• Hypertension: Initial dose is often 40 mg IR twice daily, gradually increased to 120-240 mg daily in divided doses. ER capsules can be dosed once daily (80 mg to 160 mg).
• Angina Pectoris: Starting dose is 80-320 mg daily in divided doses (IR) or once daily (ER).
• Migraine Prophylaxis: Initial dose is often 80 mg daily (in divided doses for IR or as a single ER capsule). The maintenance dose may range from 160-240 mg daily. Effects may take several weeks to manifest.
• Essential Tremor: Starting dose is 40 mg IR twice daily; typical maintenance is 120-320 mg daily.
• Administration: Immediate-release tablets can be taken with or without food, but consistency is key. Extended-release capsules must be swallowed whole and not crushed, chewed, or opened. Abrupt discontinuation should be avoided; therapy should be withdrawn gradually over 1-2 weeks under medical supervision.

Precautions

Patients should be monitored for the development of bradycardia and hypotension. Use with caution in patients with compensated heart failure. May mask the tachycardic signs of hypoglycemia in diabetic patients. Can precipitate bronchospasm in patients with reactive airway diseases (asthma, COPD). May cause or exacerbate depression. Dosage adjustment is required in patients with hepatic impairment due to its extensive liver metabolism. Caution is advised in patients with peripheral vascular disease (e.g., Raynaud’s phenomenon) as it can exacerbate symptoms.

Contraindications

Propranolol is contraindicated in patients with:

• Cardiogenic shock.
• Sinus bradycardia and greater than first-degree heart block.
• Bronchial asthma or a history of severe reactive airway disease.
• Decompensated or overt cardiac failure (unless the failure is secondary to a tachyarrhythmia treatable with propranolol).
• Severe peripheral arterial circulatory disorders.
• Hypersensitivity to propranolol or any component of the formulation.

Possible side effect

Common side effects include fatigue, bradycardia, cold extremities, nausea, diarrhea, and sleep disturbances (including vivid dreams and insomnia). Less common but more serious adverse effects can include:

• Cardiovascular: Heart failure exacerbation, heart block, severe hypotension.
• Respiratory: Bronchospasm, dyspnea.
• Central Nervous System: Depression, hallucinations, confusion.
• Gastrointestinal: Mesenteric arterial thrombosis, ischemic colitis.
• Other: Impotence, alopecia, agranulocytosis, thrombocytopenic purpura.

Drug interaction

Propranolol has a significant potential for drug interactions:

• CYP2D6 Inhibitors (e.g., Fluoxetine, Quinidine): Can increase propranolol plasma levels.
• Other Antihypertensives (e.g., Calcium channel blockers like Verapamil, Diltiazem): Increased risk of bradycardia and AV block.
• Antiarrhythmics (e.g., Disopyramide, Amiodarone): Profound negative inotropic and chronotropic effects.
• Insulin/Oral Hypoglycemics: Masks hypoglycemic tachycardia and may potentiate hypoglycemia.
• Sympathomimetics (e.g., Epinephrine, Albuterol): Antagonizes the effects of these drugs.
• NSAIDs (e.g., Ibuprofen, Naproxen): May antagonize the antihypertensive effect.

Missed dose

If a dose is missed, it should be taken as soon as remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. The patient should not take a double dose to make up for the missed one. Maintaining a consistent dosing schedule is crucial for stable therapeutic effect.

Overdose

Overdose is characterized by severe bradycardia, hypotension, heart failure, bronchospasm, and hypoglycemia. Cardiogenic shock and coma may occur. Treatment is primarily supportive and includes:

• Atropine for bradycardia.
• Beta-adrenergic agonists (e.g., Isoproterenol, Dobutamine) or a cardiac pacemaker for cardiovascular support.
• Glucagon (5-10 mg IV) is a recognized antidote, as it increases intracellular cAMP via a non-adrenergic mechanism.
• IV fluids and vasopressors (e.g., norepinephrine, epinephrine) for hypotension and shock.
• IV glucose for hypoglycemia.

Storage

Store at controlled room temperature (20°-25°C or 68°-77°F), away from light, moisture, and heat. Do not store in the bathroom. Keep all medications out of the reach of children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so.

Disclaimer

This information is for educational and professional medical reference purposes only. It is not a substitute for the professional judgment of a qualified healthcare provider in diagnosing and treating patients. The content does not cover all possible uses, directions, precautions, interactions, or adverse effects. The author and publisher disclaim any liability for any loss or risk incurred as a consequence directly or indirectly of the use and application of any of the contents of this document.

Reviews

• “A foundational agent in our cardiology practice. Its non-selectivity provides a broad mechanism of action, though it requires careful patient selection. Invaluable for post-MI care and certain arrhythmias.” – Cardiologist, 15 years experience
• “My first-line choice for prophylactic migraine management in otherwise healthy patients. The extended-release formulation offers excellent compliance. We see a significant reduction in attack frequency in a majority of our cohort.” – Neurologist, 10 years experience
• “Extremely effective for controlling essential tremor and the physical symptoms of performance anxiety. The dose response is very predictable. The main challenge is navigating its contraindications, particularly in patients with undiagnosed asthma.” – General Practitioner, 8 years experience
• “While newer, more cardioselective agents are often preferred now due to a better side effect profile, propranolol remains a powerful and cost-effective tool. Its historical data and wide range of applications secure its place in the formulary.” – Clinical Pharmacologist