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Topic Overview

How beta-blockers work

Beta-blockers are a class of drugs used to control symptoms of heart failure that are made worse by certain hormones called catecholamines. The body releases these hormones as part of its response to heart failure. For this and other reasons, beta-blockers have been shown to be effective for treating most people who have heart failure.

Beta-blockers have a variety of effects throughout the body. They are used to treat heart disease that causes chest pain, high blood pressure, heart attacks, and cardiomyopathy and irregular, rapid heartbeats (arrhythmia). Beta-blockers are also used to prevent migraine headaches, treat tremors, and control anxiety.

• Beta-blockers may work by slowing the heart rate, which allows the left ventricle (the main pumping chamber of the heart) to fill more completely.
• Some of these medicines may also help open or widen blood vessels in the body. This makes them especially useful in some people with certain forms of heart failure who may also have high blood pressure.

Bisoprolol, carvedilol, and metoprolol are some of the beta-blockers that have been tested for use in the treatment of heart failure.

Why beta-blockers are used

Beta-blockers may be used to treat left ventricular systolic dysfunction in people who are stable and have no symptoms or only mild to moderate heart failure symptoms. Beta-blockers may be used together with other medicines that are usually used to treat heart failure, such as angiotensin-converting enzyme (ACE) inhibitors or diuretics.

Beta-blockers can slow the progression of systolic forms of heart failure in many people. Beta-blockers are also used to treat heart failure with filling problems (diastolic heart failure) because they decrease the heart rate, which gives the heart more time to relax between beats. This allows the left ventricle to fill more completely and increases the volume of blood that the heart pumps with each heartbeat (ejection fraction).

How well beta-blockers work

Certain beta-blockers have been shown to:¹

• Improve the percentage of blood pumped from the left ventricle with each heartbeat (ejection fraction).
• Reduce the need for hospital stays.
• Slow the progression of heart failure.
• Reduce the risk of death caused by heart attack and heart failure.

Beta-blockers are one of four medicines recommended for use in most people who have systolic heart failure. Others include diuretics, ACE inhibitors, and sometimes digoxin.

Side effects of beta-blockers

Beta-blockers may sometimes cause a drop in blood pressure when a person stands up (orthostatic hypotension), resulting in dizziness and, rarely, fainting.

If you have diabetes and take beta-blockers, watch your blood sugar levels closely to prevent low-sugar episodes (hypoglycemia). For some people, beta-blockers can hide some symptoms of low blood sugar (hypoglycemia).

Beta-blockers may also slightly increase cholesterol levels.

Other less common side effects

• Slow heartbeats (bradycardia)
• Fluid buildup in the face, hands, legs, and feet
• Listlessness
• Fatigue
• Increased wheezing in people with asthma
• Cold hands and feet

What to think about

Beta-blockers are started only after a person's systolic heart failure has been stabilized using ACE inhibitors and diuretics.

The effect of beta-blockers may depend on the dosage used. A lower dose may have a different effect than a higher dose. Beta-blocker therapy is typically started at a low dose and increased slowly over time.

It may take a few months to see the effects of beta-blocker medicine.

Beta-blockers have been used for many years to treat high blood pressure (hypertension).