Atenolol
Tenormin
Overview
Atenolol is a cardioselective beta-1 adrenergic receptor blocker used to treat hypertension, angina, and certain arrhythmias.
Indications
- Hypertension
- Angina pectoris
- Acute myocardial infarction
Contraindications
- Severe bradycardia
- Second- or third-degree heart block
- Cardiogenic shock
- Decompensated heart failure
Classification
Mechanism of Action
Selectively blocks beta-1 adrenergic receptors in the heart, reducing heart rate, myocardial contractility, and cardiac output, and decreasing renin release.
Pharmacodynamics
Lowers blood pressure and heart rate and reduces myocardial oxygen demand. Being hydrophilic, it has limited central nervous system penetration.
Pharmacokinetics
- Absorption
- Incompletely absorbed from the GI tract; about 50% bioavailable.
- Distribution
- Low protein binding; limited lipid solubility and CNS penetration.
- Metabolism
- Minimal hepatic metabolism.
- Excretion
- Excreted largely unchanged by the kidneys.
- Half-life
- 6-7 hours
- Bioavailability
- Approximately 50%
- Protein Binding
- Approximately 3%
Dosage
Typical dosage: 25-100 mg once daily
Available Forms
- Tablet
Side Effects
Common
- Fatigue
- Bradycardia
- Cold extremities
- Dizziness
Serious
- Severe bradycardia
- Bronchospasm
- Heart failure exacerbation
Rare
- Depression
- Sexual dysfunction
Drug Interactions
Combined negative chronotropic and inotropic effects can cause severe bradycardia, heart block, or hypotension.
May mask adrenergic warning signs of hypoglycemia such as tremor and tachycardia.
Warnings
Do not discontinue chronic beta-blocker therapy abruptly, particularly in patients with coronary artery disease, as this may precipitate angina, myocardial infarction, or arrhythmias. Taper the dose gradually.
Pregnancy
Category D
Toxicity
Overdose can cause bradycardia, hypotension, bronchospasm, and heart failure.
Overdose
Manage with atropine for bradycardia, IV fluids and vasopressors for hypotension, and glucagon in refractory cases.
References
Looking for patient-friendly information? Visit RemedyDoor for easy-to-read guides about this medication.