Atenolol

A cardioselective beta-blocker used to treat high blood pressure and heart disease.

What is Atenolol?

Atenolol is a beta-1 selective adrenergic blocker commonly used in the treatment of hypertension, angina, and certain cardiac arrhythmias.

It reduces heart rate and cardiac workload.

History & Background

Atenolol was developed as a safer beta-blocker with reduced respiratory side effects compared to non-selective agents.

Chemical Structure & Properties

• IUPAC name: (RS)-2-[4-[2-hydroxy-3-(propan-2-ylamino)propoxy]phenyl]acetamide
• Molecular formula: C₁₄H₂₂N₂O₃
• Molar mass: 266.34 g/mol
• Functional groups: Amide, secondary amine, alcohol

Mechanism of Action

Atenolol lowers blood pressure by:

• Blocking β₁-adrenergic receptors
• Reducing heart rate and contractility
• Decreasing cardiac output

Pharmacokinetics

• Absorption: Moderate oral absorption
• Peak plasma time: 2–4 hours
• Half-life: 6–9 hours
• Metabolism: Minimal hepatic metabolism
• Excretion: Urine (unchanged)

Medical Uses

• Hypertension
• Angina pectoris
• Arrhythmias
• Post-myocardial infarction

Dosage Guidelines

Adults: 25–100 mg once daily

Elderly: Lower starting dose recommended

⚠️ Do not stop abruptly – taper gradually.

Side Effects

• Bradycardia
• Fatigue
• Dizziness
• Cold extremities

Warnings & Precautions

• Use cautiously in asthma and COPD
• May mask hypoglycemia symptoms
• Avoid sudden withdrawal

Drug Interactions

• Calcium channel blockers (verapamil)
• Insulin and antidiabetic drugs
• Other antihypertensives

Frequently Asked Questions

Is atenolol selective? – Yes (β₁ selective).

Does it lower heart rate? – Yes.

Is it safe long-term? – Yes, with monitoring.

Can it cause fatigue? – Common.

⚠️ Educational content only. Not a substitute for professional medical advice.