Home Drug Guide Atenolol

Drug Guide

Generic Name

Atenolol

Brand Names Tenormin

Classification

Therapeutic: Cardiovascular agent, Beta-blocker

Pharmacological: Selective beta-1 adrenergic antagonist

FDA Approved Indications

Angina pectoris
Hypertension
Prevention of myocardial infarction

Mechanism of Action

Atenolol selectively blocks beta-1 adrenergic receptors in the heart, leading to decreased heart rate, myocardial contractility, and cardiac output, ultimately reducing blood pressure and oxygen demand.

Dosage and Administration

Adult: Initially 50 mg once daily; may be increased to 100 mg once daily based on response.

Pediatric: Not typically used in children; consult specific pediatric dosing guidelines.

Geriatric: Start at lower doses due to increased sensitivity; monitor as elderly may have decreased clearance.

Renal Impairment: Adjust dose; initial dose 25-50 mg once daily, titrate as needed.

Hepatic Impairment: Use with caution; no specific adjustments specified but monitor closely.

Pharmacokinetics

Absorption: Well absorbed orally, bioavailability approximately 50-70%.

Distribution: Widely distributed; crosses the placenta, tissues, and to some extent the brain.

Metabolism: Minimal hepatic metabolism; primarily excreted unchanged by the kidneys.

Excretion: Renal excretion of unchanged drug.

Half Life: Approximately 6-7 hours.

Contraindications

Second or third-degree heart block
Severe bradycardia
Sick sinus syndrome
Uncompensated heart failure

Precautions

Use with caution in patients with asthma, COPD, diabetes (may mask hypoglycemia symptoms), peripheral vascular disease, or depression.

Adverse Reactions - Common

Fatigue (Common)
Dizziness (Common)
Bradycardia (Uncommon)

Adverse Reactions - Serious

Heart failure worsening (Uncommon)
Bronchospasm in susceptible patients (Rare)
Severe hypotension (Rare)

Drug-Drug Interactions

Verapamil, diltiazem (may increase risk of bradycardia or heart block)
Other antihypertensives (additive effect)
Insulin and hypoglycemics (may mask hypoglycemia)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood pressure, heart rate, respiratory status, and signs of heart failure.

Diagnoses:

Risk for decreased cardiac output
Impaired gas exchange
Risk for falls

Implementation: Administer with food to reduce gastrointestinal upset; monitor vital signs regularly.

Evaluation: Assess for therapeutic effectiveness (blood pressure, anginal episodes) and adverse effects.

Patient/Family Teaching

Do not discontinue abruptly—may cause tachycardia, hypertension, or ischemia.
Report signs of bradycardia, dizziness, fatigue, or worsening heart failure.
Use daily as prescribed; avoid sudden stopping.
Caution about driving or operating machinery until effects are known.

Special Considerations

Black Box Warnings: N/A

Genetic Factors: No well-established genetic factors influencing atenolol response.

Lab Test Interference: May interfere with glucose monitoring in diabetics; beta-blockers can mask hypoglycemia symptoms.

Overdose Management

Signs/Symptoms: Severe hypotension, bradycardia, heart block, bronchospasm, hypoglycemia.

Treatment: Supportive care, intravenous atropine for bradycardia, vasopressors for hypotension, airway support, and possibly dialysis in severe cases.

Storage and Handling

Storage: Store at room temperature away from light and moisture.

Stability: Stable under proper storage conditions for the duration of shelf life.