What are beta adrenergic blocking agents?

All the clinically available β-blockers are competitive antagonists. 1- Non-selective β-blockers act at both β1 and β2 receptors,(Propranolol) 2- Cardioselective β antagonists primarily block β1 receptors (Acebutolol, Atenolol) 3- Antagonists with partial agonist activity (Pindolol) These drugs also have the ability to weakly stimulate both β1 and β2 receptors and are said to have intrinsic sympathomimetic activity (ISA) 4- Antagonists of both alpha and beta adrenoceptors (Labetalol, Carvedilol)