Atenolol

Beta-1 Selective Adrenergic Blocker

Generic Name

Atenolol

Drug Class

Cardioselective β1-adrenergic receptor blocker (beta-blocker)

Indications

Hypertension
Angina pectoris
Acute myocardial infarction (post-MI therapy)
Arrhythmias (e.g., supraventricular tachycardia)
Heart failure (selected patients)

Dosage

Hypertension (adults): 25–50 mg orally once daily; may increase to 100 mg/day
Angina pectoris: 50–100 mg orally once daily
Post-MI: 50 mg orally once daily; titrate to 100 mg/day
Children: Dose must be individualized based on weight and condition; consult pediatric guidelines

Note: Adjust dose in renal impairment (creatinine clearance < 35 mL/min).

Route of Administration

Oral (tablet), IV (in selected hospital settings)

Mechanism of Action

Atenolol selectively blocks β1-adrenergic receptors in the heart, reducing heart rate, myocardial contractility, and cardiac output. This decreases blood pressure and oxygen demand in the myocardium.

Common Adverse Effects

Bradycardia
Fatigue
Dizziness
Cold extremities
Gastrointestinal upset

Serious Adverse Effects

Severe bradycardia or heart block
Heart failure exacerbation
Bronchospasm (rare, but caution in asthma)
Hypotension

Contraindications

Sinus bradycardia (< 50 bpm)
Second- or third-degree heart block
Cardiogenic shock
Severe hypotension
Known hypersensitivity to atenolol

Precautions

Use with caution in diabetes (may mask hypoglycemia symptoms)
Monitor heart rate and blood pressure regularly
Taper gradually when discontinuing to avoid rebound angina or arrhythmia
Use caution in renal impairment; adjust dose as necessary

Drug Interactions

Other antihypertensives – additive hypotensive effect
Calcium channel blockers (verapamil, diltiazem) – increased risk of bradycardia or heart block
Insulin or oral hypoglycemics – may mask hypoglycemia

Pregnancy & Lactation

Use only if clearly needed; may cause fetal bradycardia or hypoglycemia. Excreted in breast milk – monitor infant.

Patient Counseling

Take at the same time daily
Do not stop abruptly; taper gradually under medical supervision
Monitor pulse and blood pressure regularly
Report dizziness, fainting, or shortness of breath