ATENOLOL
(a-ten'oh-lole)
Apo-Atenolol , Tenormin
Classifications: autonomic nervous system agent; beta-adrenergic antagonist (sympatholytic, blocking agent); antihypertensive agent
Prototype: Propranolol
Pregnancy Category: D

Availability

25 mg, 50 mg, 100 mg tablets; 5 mg/10 mL vial

Actions

In therapeutic doses, atenolol selectively blocks beta1-adrenergic receptors located chiefly in cardiac muscle. With large doses, preferential effect is lost and inhibition of beta2-adrenergic receptors may lead to increased airway resistance, especially in patients with asthma or COPD. Mechanisms for antihypertensive action include central effect leading to decreased sympathetic outflow to periphery, reduction in renin activity with consequent suppression of the renin-angiotensin-aldosterone system, and competitive inhibition of catecholamine binding at beta-adrenergic receptor sites.

Therapeutic Effects

Reduces rate and force of cardiac contractions (negative inotropic action); cardiac output is reduced, as well as systolic and diastolic BP. Atenolol decreases peripheral vascular resistance both at rest and with exercise.

Uses

Management of hypertension as a single agent or concomitantly with other antihypertensive agents, especially a diuretic, and in treatment of stable angina pectoris, MI.

Unlabeled Uses

Antiarrhythmic, mitral valve prolapse, adjunct in treatment of pheochromocytoma and of thyrotoxicosis; and for vascular headache prophylaxis.

Contraindications

Sinus bradycardia, greater than first-degree AV heart block, uncompensated heart failure, cardiogenic shock, peripheral vascular disease, Raynaud's disease, hypotension; abrupt discontinuation, pulmonary edema. Safety during pregnancy (category D), or lactation is not established.

Cautious Use

Hypertensive patients with CHF controlled by digitalis and diuretics, vasospastic angina (Prinzmetal's angina); asthma, bronchitis, emphysema, and COPD; major depression; diabetes mellitus; impaired renal function, dialysis; myasthenia gravis; pheochromocytoma, hyperthyroidism, thyrotoxicosis; older adults.

Route & Dosage

Hypertension, Angina
Adult: PO 25–50 mg/d, may increase to 100 mg/d
Child: PO 0.8–1.5 mg/kg/d (max: 2 mg/kg/d)

MI
Adult: PO 10 min after second IV dose, start 50 mg/d IV 5 mg q5min times 2 doses, then switch to PO

Administration

Oral
Intravenous

PREPARE: Direct: Use undiluted or diluted in 10–50 mL of NS, D5W, D5/NS, D5/0.45NS, or 0.45NS.  

ADMINISTER: Direct: Give over 5 min.  

Adverse Effects (1%)

CNS: Dizziness, vertigo, light-headedness, syncope, fatigue or weakness, lethargy, drowsiness, insomnia, mental changes, depression. CV: Bradycardia, hypotension, CHF, cold extremities, leg pains, dysrhythmias. GI: Nausea, vomiting, diarrhea. Respiratory: Pulmonary edema, dyspnea, bronchospasm. Other: May mask symptoms of hypoglycemia; decreased sexual ability.

Interactions

Drug: Atropine and other anticholinergics may increase atenolol absorption from GI tract; nsaids may decrease hypotensive effects; may mask symptoms of a hypoglycemic reaction induced by insulin, sulfonylureas; may increase lidocaine levels and toxicity; pharmacologic and toxic effects of both atenolol and verapamil are increased. Prazosin, terazocin may increase severe hypotensive response to first dose of atenolol.

Pharmacokinetics

Absorption: 50% of PO dose absorbed. Peak: 2–4 h PO; 5 min IV. Duration: 24 h. Distribution: Does not readily cross blood–brain barrier. Metabolism: No hepatic metabolism. Elimination: 40–50% excreted in urine; 50–60% excreted in feces. Half-Life: 6–7 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug