Overview
Propranolol is a non-selective beta-adrenergic blocking agent used primarily for cardiovascular conditions. It works by blocking beta-1 and beta-2 adrenergic receptors, reducing heart rate, blood pressure, and myocardial oxygen demand. This medication is available in various formulations including extended-release capsules for chronic management.
Mechanism of Action
Propranolol competitively blocks both beta-1 and beta-2 adrenergic receptors. This non-selective beta-blockade decreases heart rate, myocardial contractility, and blood pressure while reducing renin release and myocardial oxygen consumption.
Indications
- Hypertension
- Angina pectoris
- Cardiac arrhythmias (especially supraventricular tachycardias)
- Migraine prophylaxis
- Essential tremor
- Hypertrophic subaortic stenosis
- Pheochromocytoma (with alpha-blockade)
- Myocardial infarction (secondary prevention)
Common Doses
- 10 mg
- 20 mg
- 40 mg
- 60 mg
- 80 mg
- 120 mg
- 160 mg
Dosage
Dosage varies by indication: Hypertension typically starts at 40 mg twice daily, increasing gradually. Angina management begins with 80-320 mg daily in divided doses. Migraine prophylaxis uses 80-240 mg daily. Extended-release formulations allow once-daily dosing for maintenance therapy.
Contraindications
- Cardiogenic shock
- Sinus bradycardia and greater than first-degree heart block
- Bronchial asthma
- Known hypersensitivity to propranolol hydrochloride
Side Effects
- Bradycardia
- Fatigue
- Dizziness
- Nausea
- Cold extremities
- Depression
- Insomnia
- Bronchospasm
- Hypotension
- Heart failure exacerbation
- Impotence
Interactions
- CYP2D6, 1A2, or 2C19 inhibitors may increase propranolol levels
- Alcohol may enhance hypotensive effects
- Calcium channel blockers (verapamil, diltiazem) may cause additive cardiac depression
- NSAIDs may reduce antihypertensive effect
- Insulin and oral hypoglycemics require dose monitoring
Counseling Points
- Do not stop abruptly; taper under medical supervision
- Monitor pulse rate and blood pressure regularly
- Report dizziness, shortness of breath, or swelling of extremities
- May cause fatigue; use caution when driving or operating machinery
- Take with food to enhance absorption
- Diabetics should monitor blood glucose closely