Beta-blockers for heart attack and unstable angina


Generic Name Brand Name
acebutolol Sectral
atenolol Tenormin
carvedilol Coreg
labetalol Trandate
metoprolol Lopressor, Toprol XL
penbutolol Levatol
propranolol Inderal

How It Works

The body often responds to the increased stress of a heart attack or unstable angina by increasing the heart rate and blood pressure. Beta-blockers slow the heart rate and reduce the heart's workload.

Why It Is Used

Beta-blockers reduce heart rate, blood pressure, and the workload of the heart. When the heart does not have to work as hard, it requires less oxygen. This in turn can help relieve or prevent chest pain (angina). Beta-blockers are often used with other medicines to treat a heart attack in progress. Beta-blockers are also used to treat an abnormal heartbeat (arrhythmia).

How Well It Works

Beta-blockers given within hours of the start of a heart attack may lower the risk of early death after a heart attack.

For people who have had a heart attack, beta-blockers lower the risk of another heart attack and lower the risk of sudden death.1

Side Effects

Side effects of beta-blockers may include:

  • Fatigue, drowsiness, or trouble sleeping.
  • Decreased blood flow to the feet and hands, which causes them to feel cold, and increased leg pain brought on by exertion (intermittent claudication).
  • Dizziness and lightheadedness.

In people who have diabetes, beta-blockers can increase blood sugar levels. Also, they may cover up warning signs of low blood sugar (hypoglycemia), such as a change in pulse rate, which increases your risk of low blood sugar episodes.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Most people will take beta-blockers for a long time after a heart attack and maybe for the rest of their lives.

You may not be able to take beta-blockers if you have very low blood pressure or a low heart rate. Beta-blockers could make both of these problems worse.

Beta-blockers may make other medical conditions worse. Examples of other conditions are asthma, heart failure, diabetes, and certain heart arrhythmias. You may have to stop taking beta-blockers if your condition gets worse or if side effects develop and continue.

If you have food, medicine, or insect-sting allergies, beta-blockers may cause allergic reactions to be worse and harder to treat. If you have a severe allergic reaction, tell your doctor that you are taking a beta-blocker.

Fainting and lightheadedness are more likely to occur when you first start taking a beta-blocker or when the dose is increased. These symptoms may also increase when you drink alcohol or stand for long periods of time, especially in hot weather. Try getting up slowly from either a lying or sitting position. If the problem continues or gets worse, check with your doctor.

Do not suddenly stop taking beta-blockers without first talking with your doctor. The risk of heart attack may be increased when beta-blockers are stopped suddenly.

Beta-blockers tend to decrease blood circulation in the skin, fingers, and toes and may make you more sensitive to cold temperatures. Take precautions by dressing warmly and avoiding prolonged exposure to cold.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.



  1. Gami A (2006). Secondary prevention of ischaemic cardiac events, search date July 2004. Online version of Clinical Evidence (15): 1–31.

Last Updated: May 5, 2009

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