Atenolol vs Propranolol
## Overview
Atenolol and propranolol differ fundamentally in receptor selectivity. Atenolol is cardioselective (beta-1), while propranolol is non-selective. This determines their suitability in specific patient populations.
## Mechanism of Action
Atenolol selectively blocks beta-1 receptors at therapeutic doses. Propranolol blocks both beta-1 and beta-2 with equal potency and also possesses membrane-stabilizing activity (Class I antiarrhythmic action) at high doses.
## Pharmacokinetics
Atenolol is hydrophilic (~50% absorption, ~80–90% renal excretion unchanged, half-life 6–9 h). Propranolol is highly lipophilic (nearly complete gut absorption, 90%+ first-pass extraction, bioavailability ~25–30%, half-life 3–6 h).
## Indications
Both are used for hypertension and angina. Propranolol is uniquely indicated for essential tremor, hyperthyroidism (perioperative), portal hypertension, pheochromocytoma (after alpha-blockade), and migraine prophylaxis. Atenolol is not used for these conditions.
## Safety
Propranolol is contraindicated in asthma and COPD. Atenolol can be cautiously used in COPD (mild) but not asthma. Atenolol's hydrophilicity means fewer CNS effects.
## Key Takeaways
- Atenolol: cardioselective, hydrophilic, renally cleared, fewer CNS effects
- Propranolol: non-selective, lipophilic, broad indications including tremor and thyrotoxicosis
บทสรุป
Propranolol is required when non-selective beta-blockade is needed (tremor, thyrotoxicosis, portal hypertension). For hypertension and cardiac indications in patients with pulmonary disease, atenolol is preferred.