Atenolol: Uses, How to Take (with Dosing) & Side Effects

Updated in December 2023

Atenolol is a hypertensive medication indicated for the treatment of cardiovascular diseases, such as high blood pressure, cardiac arrhythmias, and angina. Atenolol works by slowing down the heart rate and by reducing the heart's contractility (the force it exerts to pump blood). Atenolol also dilates the blood vessels to improve blood flow and circulation. 

This medication can be purchased at the pharmacy and is available in concentrations of 25, 50 or 100 mg. This medication can also be found combined with another substance, chlorthalidone, a diuretic that stimulates urine elimination to improve atenolol’s effect. 

Atenolol should only be used as prescribed, in the doses and for the duration indicated by your doctor. 

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Common uses

Atenolol is indicated for the treatment of cardiovascular diseases like: 

  • Chest pain (angina)
  • High blood pressure
  • Cardiac arrhythmias 
  • Myocardial infarct 

Atenolol should be used as directed by the doctor for the specific condition being treated. 

How to take

Atenolol is taken orally with a cup of water at the same time every day. The 25mg pill should be taken whole, while the 50mg and 100mg pills can be cut. 

The recommended doses for atenolol vary depending on the condition being treated: 

  • High blood pressure: The recommended dose is 50 to 100 mg of atenolol per day, as a single dose
  • Angina: The recommended dose is 100 mg per day as a single dose, or 50 mg per day twice day. 
  • Cardiac arrhythmia: The recommended dose is 50 mg to 100 mg of atenolol per day as a single dose for cases of controlled arrhythmias. 
  • Myocardial infarct: The recommended dose after a heart attack is 100 mg per day as a single dose. It is taken to prevent a recurrence. 

Atenolol starts to take effect within an hour after taking, with its maximum effect reached within 2 to 4 hours. However, it will remain effective in the body for at least 24 hours. 

This medication may take 2 weeks to reach its therapeutic effect. You should not discontinue use on your own without speaking to your doctor first, as it can worsen the disease. 

Side effects

Some of the most common side effect that can occur during atenolol treatment are dizziness, fatigue, cold hands and feet, depression, cardiac failure or pulmonary embolism. 

It is important to seek urgent medical assistance if you have symptoms like worsening chest pain, decreased heart rate, irregular heart rate, dizziness, fainting, shortness of breath even without major exertion, sudden weight gain, or cold sensation in the hands and feet. 

In addition, atenolol can cause severe allergic reactions that may require immediate medical attention. Stop treatment immediately and proceed to the emergency room if you notice symptoms like difficulty breathing, the sensation of a closing throat, and swelling of the mouth, tongue or face. 

Contraindications for use

Atenolol should not be used by children, breastfeeding women, pregnant women or women looking to get pregnant.

This medication should not be used by people with slow heart rates, low blood pressure, a mechanical heart pump problem, circulation problem, uncontrolled  cardiac failure, electrical heart problems, benign tumors in the adrenal or suprarenal glands, or metabolic acidosis. 

Atenolol should also not be used by people with an allergy to any of the components in the pill. 

Atenolol should be used cautiously by diabetics, as it can mask some of the symptoms of high blood sugar, like increased heart rate.