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Drug Info

What is a beta blocker?

Cropped SingleCare logo By | February 11, 2020
Medically reviewed by Karen Berger, Pharm.D.

High blood pressure (hypertension) is a very common health condition in the United States with more than three million cases per year. It is called a “silent killer” because many people do not experience symptoms and unknowingly live with the condition until a serious event, like a stroke or heart attack, occurs.

If you have high blood pressure, your doctor may prescribe a beta blocker. Unlike other antihypertensive drugs, beta blockers can actually help alleviate symptoms like chest pain, sweating, and trembling.

Use this guide to learn how beta blockers work, how they treat your conditions, and what side effects to expect.

What is a beta blocker? 

Beta blockers are a type of medication that help manage conditions such as high blood pressure, abnormal heart rhythms, and congestive heart failure.

Beta blockers (beta-adrenergic blocking agents) work by blocking the effects of stress hormones like norepinephrine and epinephrine (adrenaline). These hormones are a part of the sympathetic nervous system and can cause symptoms like increased heart rate and high blood pressure. By blocking these hormones, beta blockers can slow the heartbeat down, lower blood pressure, and improve blood flow by relaxing blood vessels. They reduce the effects of stress hormones on the heart muscle itself.   

There are three types of beta receptors in the body that control different functions based on their location. Beta-1 receptors are mainly in the heart, eyes, and kidneys. Beta-2 receptors are found in the lungs, liver, GI tract, and blood vessels. Beta-3 receptors are found in fat cells. Beta blockers work by keeping chemical messengers from binding to beta-1 and beta-2 receptors. This process keeps norepinephrine and epinephrine from constricting blood vessels and increasing blood pressure and heart rate. 

What are the benefits of beta blockers?

Beta blockers have many health benefits. They are typically prescribed to treat cardiovascular diseases and high blood pressure. They can help treat irregular heartbeats, heart failure, chest pain, and even help with physical symptoms that come with anxiety, like sweating and trembling. 

“Beta blockers are most commonly used to reduce stress on the heart in people who have had heart attacks or who have severe atherosclerotic heart disease,” says Tomas Ayala, MD, a cardiologist at The Heart Center at Reisterstown. “They can reduce the risk of future heart attacks and can also help to control angina—chest discomfort related to heart disease. Beta blockers are also used to treat certain cardiac arrhythmias.”

“Arrhythmias such as atrial fibrillation, atrial flutter, or supraventricular tachycardia can result in abnormally rapid heart rates, and beta blockers are frequently used to slow down the heart rate,” says Dr. Ayala. “One specific beta blocker, propranolol, can also be used to help treat essential tremors (tremors without underlying disease process) and to help prevent migraine headaches.” 

Here’s a longer list of some of the conditions that the FDA has approved beta blockers to treat: 

  • Aortic dissection
  • Cardiac arrhythmias
  • Congestive heart failure
  • Myocardial infarction
  • Coronary artery disease
  • Essential tremor
  • Glaucoma 
  • Hyperthyroidism
  • Hypertension
  • Migraine prophylaxis
  • Portal hypertension
  • Tachycardia 

This list is not comprehensive. Doctors and researchers are looking for new ways to use these medications to help people. For example, one study by the University of Dundee explains how long-term use of beta blockers may even help people with asthma experience fewer symptoms. 

What are the side effects of beta blockers?

As with any medication, there is always the potential for side effects. Taking beta blockers with food may help reduce side effects because this causes the body to absorb the medication more slowly. The following list of side effects is not comprehensive. Speak with your doctor or a medical professional for a complete list of side effects.

  • Cold hands and feet
  • Constipation 
  • Depression
  • Dizziness
  • Dry mouth, skin, and eyes 
  • Erectile dysfunction 
  • Lightheadedness
  • Fatigue
  • Headache
  • Nausea 
  • Shortness of breath
  • Slow heartbeat 
  • Trouble sleeping 
  • Weight gain 

Some side effects can be more serious. For example, beta blockers have been known to cause severe asthma attacks for some people who have asthma.

Although rare, an allergic reaction is possible. Allergic reactions can cause difficulty breathing, facial swelling, and hives. You should seek medical attention immediately if you believe you are experiencing an allergic reaction. 

Warnings

Blood pressure levels and heart rate must be monitored on a consistent basis while taking beta blockers, as they may also cause heart block or heart failure in patients with heart problems.

For people with diabetes, beta blockers may keep the body from showing signs of low blood sugar, such as having a fast heartbeat (tachycardia).

Beta blocker use during pregnancy depends on a number of factors, which your healthcare provider will evaluate. If you’re pregnant or may become pregnant and are already taking a beta blocker, talk with your doctor to determine whether you should continue taking your medication.

It’s possible that beta blockers will affect cholesterol and triglyceride levels. They can potentially raise triglyceride levels and decrease “good” cholesterol levels. Although this is more common in patients with metabolic syndrome, these changes are usually only temporary. 

Interactions

Taking beta blockers and certain medications at the same time could be harmful. Non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen, anti-arrhythmic drugs, antihypertensive drugs, and anti-anginal drugs are all examples of classes of medications that may interfere with the efficacy of beta blockers. Talking with a doctor or medical professional is the best way to determine whether or not beta blockers are right for you, and if they are compatible with other medications you are taking. 

Types of beta blockers

Beta blockers can be classified as either selective or non-selective. Non-selective beta blockers affect the entire body except for the heart. Selective beta blockers affect only the heart.

Not all beta blockers treat the same conditions. Some health conditions may require a selective beta blocker, while others may require a non-selective beta blocker.

Selective beta blockers block beta-1 receptors, which can affect the heart muscle. On the other hand, non-selective beta blockers block beta-1 and beta-2 receptors, which can affect the heart muscle along with blood vessels.

What are the most common beta blockers?

Beta blockers can come in the form of a capsule or tablet (immediate- or extended-release), solution, or injection. At the beginning of treatment, a doctor will likely prescribe a low initial dose of medication and gradually increase it on a weekly basis until the right dosage is found.

The length of treatment varies from person to person based on individual symptoms and response to treatment. However, most people take beta blockers for a long period of time with regular checkups and measurements of blood pressure and heart rate. 

Here’s a list of some of the most commonly prescribed beta blockers: 

“The most common beta blockers are metoprolol (which comes in a short-acting form–metoprolol tartrate-and a long-acting form–metoprolol succinate), carvedilol, bisoprolol, atenolol, and propranolol,” says Dr. Ayala. “As you have noticed, that ending ‘–lol’ is common to beta blockers and is a good clue that a given medication is likely to be one.”

Alternatives

For some people, beta blockers might not be enough to treat their condition. As a result, doctors will sometimes prescribe a beta blocker with another type of medication.

One common example is a drug class called ACE inhibitors. ACE inhibitors treat many of the same conditions but they work in a different way. ACE (angiotensin-converting enzyme) inhibitors keep a substance called angiotensin I from converting to angiotensin II, thereby keeping blood vessels from narrowing and constricting. 

The two medications work differently and target different parts of the body. Taking both types of medications at the same time may be required for people with chronic heart failure, people who’ve had a heart attack, or for people with extremely high blood pressure. Talking with your doctor is the best way to determine which type of medication is right for you based on your individual medical condition.