Atenolol is a 2nd-generation, β1-selective beta-blocker.

It reduces heart rate, contractility, and renin release with minimal β2 blockade at usual doses.

Classification: • 2nd Generation (Cardioselective) • No intrinsic sympathomimetic activity (ISA)

→ Beta-Blockers Overview

Selective β1 blockade:

• ↓ Heart rate • ↓ Contractility • ↓ AV nodal conduction • ↓ Renin release

Net Effects:

• ↓ Cardiac output • ↓ Blood pressure • ↓ Myocardial oxygen demand

Selectivity is dose-dependent.

• Historically widely used • Not first-line for uncomplicated HTN • Inferior outcome data compared to other agents

→ Hypertension Module

• Reduces myocardial oxygen demand • Used for chronic stable angina

→ Anti-Anginal Module

• Rate control (less commonly used than metoprolol)

→ Dysrhythmias Module

Atenolol does NOT have proven mortality benefit in HFrEF.

Evidence-based HFrEF beta-blockers are:

• Carvedilol • Metoprolol Succinate • Bisoprolol

→ Heart Failure Module

This is a common exam distinction.

• Hydrophilic (less CNS penetration than propranolol) • Primarily renally excreted • Once-daily dosing common

Dose adjustment required in renal impairment.

• Bradycardia • Hypotension • Fatigue • Cold extremities • Masked hypoglycemia

Lower bronchospasm risk than nonselective agents.

• Severe bradycardia • High-grade AV block (without pacemaker) • Cardiogenic shock • Acute decompensated heart failure

Use caution in: • Asthma (safer than nonselective agents) • Diabetes • Renal impairment

Metoprolol: • More commonly used today • Stronger outcome data • Succinate form reduces mortality in HFrEF

Atenolol: • Older agent • Less outcome data in hypertension • No mortality benefit in HFrEF

✔ β1 selective ✔ Renally cleared ✔ No proven HFrEF mortality benefit ✔ Not first-line for uncomplicated hypertension ✔ Historically common but declining use

Related:

→ Beta-Blockers Overview → Hypertension Module → Anti-Anginal Module → Heart Failure Module → Return to Cardiovascular Modules