Beta antagonists are beta blockers: drugs that inhibit beta-adrenergic receptor activation. The term includes nonselective, beta-1-selective and vasodilating subgroups.

Beta-1 blockade reduces heart rate, contractility, conduction and renin release. Beta-2 blockade can cause bronchoconstriction and alter glucose and potassium responses.

Propranolol, nadolol, timolol, metoprolol, bisoprolol, atenolol, esmolol, carvedilol, labetalol and nebivolol are important members.

Uses include ischaemic heart disease, selected arrhythmias, HFrEF with evidence-based agents, hypertension with compelling indications, aortic disease, migraine prevention, essential tremor, portal hypertension and glaucoma.

Bradycardia, hypotension, fatigue, exercise intolerance and conduction block may occur. Nonselective blockade can cause bronchospasm and delay recovery from hypoglycaemia.

Avoid in cardiogenic shock, severe bradycardia and advanced unpaced heart block. Use receptor selectivity and clinical evidence—not the class name alone—to choose an agent, and taper chronic therapy.