General

Pronunciation:
a-ten-oh-lole

Trade Name(s)

• Tenormin

Ther. Class.

antianginals

antihypertensives

Pharm. Class.

beta blockers

Indications

• Hypertension.
• Angina pectoris.
• MI.

Action

Blocks stimulation of beta₁ (myocardial)-adrenergic receptors. Does not usually affect beta₂ (pulmonary, vascular, uterine)-receptor sites.

Therapeutic Effect(s):

• Decreased BP and heart rate.
• Decreased frequency of attacks of angina pectoris.
• Reduction of cardiovascular mortality associated with MI.

Pharmacokinetics

Absorption: 50–60% absorbed after oral administration.

Distribution: Minimal penetration of CNS.

Metabolism and Excretion: 40–50% excreted unchanged by the kidneys; remainder excreted in feces as unabsorbed drug.

Half-life: 6–9 hr.

TIME/ACTION PROFILE (cardiovascular effects)

Contraindication/Precautions

Contraindicated in:

• Decompensated HF;
• Pulmonary edema;
• Cardiogenic shock;
• Bradycardia or heart block.

Use Cautiously in:

• Renal impairment (dosage ↓ recommended if CCr ≤35 mL/min);
• Hepatic impairment;
• Pulmonary disease (including asthma; beta selectivity may be lost at higher doses);
• Diabetes mellitus (may mask signs of hypoglycemia);
• Thyrotoxicosis (may mask symptoms);
• Patients with a history of severe allergic reactions (intensity of reactions may be ↑);
• OB:  Crosses the placenta and may cause fetal/neonatal bradycardia, hypotension, hypoglycemia, or respiratory depression;
• Lactation:  Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
• Pedi:   Safety and effectiveness not established in children;
• Geri:  Older adults may have ↑ sensitivity to beta blockers (initial dose ↓ recommended).

Adverse Reactions/Side Effects

CV: BRADYCARDIA, HF, hypotension, peripheral vasoconstriction

Derm: rash

EENT: blurred vision, stuffy nose

Endo: hyperglycemia, hypoglycemia

GI: ↑ liver enzymes, constipation, diarrhea, nausea, vomiting

GU: erectile dysfunction, ↓ libido, urinary frequency

MS: arthralgia, back pain, joint pain

Neuro: fatigue, weakness, anxiety, depression, dizziness, drowsiness, insomnia, memory loss, mental status changes, nervousness, nightmares

Resp: bronchospasm, PULMONARY EDEMA, wheezing

Misc: drug-induced lupus syndrome

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

•  General anesthesia,  phenytoin, and  verapamil  may cause additive myocardial depression.
• Additive bradycardia may occur with  clonidine,  digoxin,  diltiazem,  ivabradine, and  verapamil.
• Additive hypotension may occur with other  antihypertensives, acute ingestion of  alcohol, or  nitrates.
• Concurrent use with  amphetamine,  cocaine,  ephedrine,  epinephrine,  norepinephrine,  phenylephrine, or  pseudoephedrine  may result in unopposed alpha-adrenergic stimulation (excessive hypertension, bradycardia).
• Concurrent  thyroid  administration may ↓ effectiveness.
• May alter the effectiveness of  insulins  or  oral hypoglycemic agents ; dosage adjustments may be necessary.
• May ↓ the effectiveness of  theophylline.
• May ↓ the beneficial beta₁ -cardiovascular effects of  dopamine  or  dobutamine.
• Use cautiously within 14 days of  MAO inhibitor  therapy; may result in hypertension.

Route/Dosage

PO (Adults): Antianginal:  50 mg once daily; may ↑ after 1 wk to 100 mg/day (up to 200 mg/day).  Antihypertensive:  25–50 mg once daily; may ↑ after 2 wk to 50–100 mg once daily.  MI:  50 mg, then 50 mg 12 hr later, then 100 mg/day as a single dose or in 2 divided doses for 6–9 days or until hospital discharge.

Renal Impairment 
PO (Adults): CCr 15–35 mL/min:  Do not exceed 50 mg/day;  CCr <15 mL/min:  Do not exceed 50 mg every other day.

Availability (generic available)

Tablets: 25 mg, 50 mg, 100 mg

In Combination with: chlorthalidone (Tenoretic). See combination drugs.

Assessment

• Monitor BP, HR, and ECG frequently during dose adjustment period and periodically throughout therapy.
• Monitor intake and output and daily weights. Assess routinely for HF (dyspnea, rales/crackles, weight gain, peripheral edema, jugular venous distention).
• Angina: Assess frequency and characteristics of angina periodically during therapy.

Lab Test Considerations:

May cause ↑ glucose and triglycerides.

Monitor patients receiving beta blockers for signs of overdose (bradycardia, severe dizziness or fainting, severe drowsiness, dyspnea, bluish fingernails or palms, seizures). Notify health care provider immediately if these signs occur.

Implementation

• PO Take apical pulse before administering drug. If <50 bpm or if arrhythmia occurs, withhold medication and notify health care provider.

Patient/Family Teaching

• Black Box:  Instruct patient to take atenolol as directed at the same time each day, even if feeling well; do not skip or double up on missed doses. Take missed doses as soon as possible up to 8 hr before next dose. Abrupt withdrawal may cause life-threatening arrhythmias, hypertension, or myocardial ischemia.
• Teach patient and family how to check pulse and BP. Instruct them to check pulse daily and BP biweekly and to report significant changes.
• May cause drowsiness or dizziness. Caution patients to avoid driving or other activities that require alertness until response to the drug is known.
• Advise patients to change positions slowly to minimize orthostatic hypotension.
• Caution patient that atenolol may ↑ sensitivity to cold.
• Instruct patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken; to avoid alcohol; and to consult health care provider before taking any new medications, especially cold preparations.
• Patients with diabetes should closely monitor blood glucose, especially if weakness, malaise, irritability, or fatigue occurs. Medication does not block sweating as a sign of hypoglycemia.
• Advise patient to notify health care provider if slow pulse, difficulty breathing, wheezing, cold hands and feet, dizziness, light-headedness, confusion, depression, rash, fever, sore throat, unusual bleeding, or bruising occurs.
• Instruct patient to inform health care provider of medication regimen before treatment or surgery.
• Rep:  Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected or if breastfeeding.
• Advise patient to carry identification describing disease process and medication regimen at all times.
• Hypertension: Reinforce the need to continue additional therapies for hypertension (weight loss, sodium restriction, stress reduction, regular exercise, moderation of alcohol consumption, smoking cessation). Medication controls but does not cure hypertension.

Evaluation/Desired Outcomes

• Decrease in BP.

• Reduction in frequency of angina.

  • Increase in activity tolerance.
• Prevention of MI.