Author: Mr. Ashutosh Jain
Volume: 01
First Online: 31 August 2024
Pages: 87-101
DOI:

Beta adrenergic blockers, commonly known as beta blockers, inhibit the action of catecholamines on beta receptors, primarily affecting the heart and vascular system. The structure-activity relationship (SAR) of beta blockers reveals that modifications to the aromatic ring and side chains can significantly influence their selectivity and affinity for beta-1 and beta-2 receptors. For instance, propranolol, a non-selective beta blocker, effectively reduces heart rate and blood pressure but can also cause bronchoconstriction due to beta-2 receptor blockade. Selective beta-1 blockers like atenolol, metoprolol, bisoprolol, and esmolol are designed to minimize respiratory side effects by preferentially targeting beta-1 receptors in the heart, making them safer for patients with respiratory conditions. Metibranolol and betaxolol also fall into this category, offering cardiac protection with reduced risk of bronchospasm. Labetalol and carvedilol are unique in that they block both alpha and beta receptors, providing a dual mechanism that is particularly useful in treating hypertension and heart failure. The SAR of beta blockers enables the fine-tuning of their therapeutic effects, ensuring that these medications can be tailored to meet specific clinical needs while minimizing adverse effects.