Reviewed on 3/14/2022

What Is Atenolol and How Does It Work?

Atenolol is used with or without other medications to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. This medication is also used to treat chest pain (angina) and to improve survival after a heart attack.

  • Atenolol belongs to a class of drugs known as beta-blockers. It works by blocking the action of certain natural chemicals in your body, such as epinephrine, on the heart and blood vessels. This effect lowers the heart rate, blood pressure, and strain on the heart.
  • Atenolol may also be used to treat irregular heartbeat, heart failure, alcohol withdrawal symptoms, and to prevent migraine headaches.
  • Atenolol is available under the following different brand names: Tenormin.

What Are Dosages of Atenolol?

Dosages of Atenolol

Adult and Pediatric Dosage Forms and Strengths


  • 25 mg
  • 50 mg
  • 100 mg
Dosage Considerations – Should be Given as Follows: Hypertension
  • Adult: 25-50 mg/day orally initially; may be increased to 100 mg/day orally
  • Pediatric (Off-label): 0.5-1 mg/kg/day orally; not to exceed 2 mg/kg/day or 100 mg/day
  • Geriatric: 25 mg/day orally initially; may be increased to 100 mg/day orally
Angina Pectoris
  • Adult: 50 mg/day orally; after 1 week, may be increased to 100 mg/day orally; some patients may require 200 mg/day
  • Geriatric: 25 mg/day orally; after 1 week, may be increased to 100 mg/day; some patients may require 200 mg/day
Post Myocardial Infarction (MI)

Secondary prevention

  • Adult: 100 mg orally once daily or divided every 12 hours for 6-9 days after myocardial infarction (MI)
  • Geriatric: 100 mg orally once daily or divided every 12 hours for 6-9 days after MI
Alcohol Withdrawal Syndrome (Off-label)
  • 50-100 mg/day orally
Supraventricular Arrhythmias (Off-label)
  • Prevention
  • 50 mg/day orally, beginning up to 3 days before surgery and continued until 7 days after surgery; may be increased to 100 mg/day
Thyrotoxicosis (Off-label)
  • 25-100 mg orally once daily or divided every 12 hours
Dosing Modifications
  • CrCl 15-35 mL/min/1.73 m²: Not to exceed 50 mg/day orally
  • CrCl less than 15 mL/min/1.73 m²: Not to exceed 25 mg/day orally
  • CrCl greater than 35 mL/min/1.73 m²: Dose adjustment not necessary
Dosing Considerations
  • Geriatric: It may be necessary to initiate dosing at 25 mg/day orally

What Are Side Effects Associated with Using Atenolol?

Side effects of atenolol include:

Other side effects of atenolol include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Atenolol?

If your doctor has directed you to use this medication for diabetes, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

Severe interactions of atenolol include:

  • There are no known severe reactions with the use of atenolol.
  • Atenolol has serious interactions with at least 21 different drugs.
  • Atenolol has moderate interactions with at least 175 different drugs.
  • Atenolol has mild interactions with at least 40 different drugs.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Atenolol?


  • Ischemic heart disease may be exacerbated after abrupt withdrawal.
  • Hypersensitivity to catecholamines has been observed during withdrawal.
  • Exacerbation of angina and, in some cases, myocardial infarction (MI) may occur after abrupt discontinuance.
  • When long-term beta-blocker therapy (particularly with ischemic heart disease) is discontinued, dosage should be gradually reduced over 1-2 weeks with careful monitoring.
  • If angina worsens markedly or acute coronary insufficiency develops, beta-blocker administration should be promptly reinitiated, at least temporarily (in addition to other measures appropriate for unstable angina).
  • Patients should be warned against interruption or discontinuance of beta-blocker therapy without physician advice.
  • Because coronary artery disease (CAD) is common and may be unrecognized, beta-blocker therapy must be discontinued slowly, even in patients treated only for hypertension.
  • This medication contains atenolol. Do not take Tenormin if you are allergic to atenolol or any ingredients contained in this drug.
  • Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


Effects of Drug Abuse

  • None.

Short-Term Effects

  • See "What Are Side Effects Associated with Using Atenolol?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Atenolol?"


  • Use with caution in anesthesia or surgery (myocardial depression), bronchospastic disease, cerebrovascular insufficiency, diabetes mellitus, hyperthyroidism or thyrotoxicosis, liver disease, renal impairment, peripheral vascular disease, compromised left ventricular function, advanced age, heart failure.
  • May mask the effects of hyperthyroidism.
  • Risk of hypoglycemia and bradycardia in neonates born to mothers who receive the drug at parturition or while breastfeeding, especially in premature infants and those with renal impairment.
  • Use with caution in patients taking calcium-channel blockers or cardiac glycosides or using inhaled anesthetics.
  • Avoid abrupt withdrawal; sudden discontinuance can exacerbate angina and lead to MI.
  • Increased risk of stroke after surgery.
  • In patients receiving clonidine, atenolol should be discontinued several days before the withdrawal of clonidine.
  • May cause or exacerbate CNS depression (use with caution in patients with psychiatric illness).
  • Use in pheochromocytoma (alpha blockade required before use of beta-blocker).
  • Consider preexisting conditions such as sick sinus syndrome before initiating therapy.
  • May potentiate hypoglycemia and may mask its signs and symptoms in patients with diabetes mellitus; use caution.
  • Monitor for worsening of heart failure symptoms in patients with compensated heart failure.
  • Use caution in patients with myasthenia gravis; may precipitate or aggravate symptoms of arterial insufficiency in patients with Raynaud's disease and peripheral vascular disease; use caution and monitor for progression of arterial obstruction.
  • Avoid beta-blockers without alpha1-adrenergic receptor blocking activity in patients with Prinzmetal variant angina; unopposed alpha1-adrenergic receptors mediate coronary vasoconstriction and can worsen anginal symptoms.
  • Exacerbation or induction of psoriasis reported with beta-blocker use; cause and effect not established.

Pregnancy and Lactation

  • Use atenolol during pregnancy only in LIFE-THREATENING emergencies when no safer drug is available. There is positive evidence of human fetal risk.
  • Atenolol enters breast milk; neonates born to mothers who are receiving atenolol at parturition or breastfeeding may be at risk for hypoglycemia and bradycardia; use with caution if breastfeeding.

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