What Do Beta-Blockers Treat and How Do They Work?

Beta-blockers are a class of prescription medications commonly used to treat conditions related to your heart and blood vessels. For example, your healthcare provider may prescribe a beta-blocker to help lower your blood pressure or treat heart failure.

Beta-blockers are some of the most commonly prescribed drugs in the United States. According to the Centers for Disease Control and Prevention (CDC), about 22% of older Americans (ages 60 to 79) take a beta-blocker for high blood pressure or heart disease.

Some commonly prescribed beta-blockers are Lopressor (metoprolol), Tenormin (atenolol), and Coreg (carvedilol).

This article will discuss the uses and types of beta-blockers, how they work, how to take them safely, and their advantages versus disadvantages.

Uses of Beta-Blockers

Most beta-blockers are used to treat heart conditions, including:

• High blood pressure
• Heart failure
• Enlarged heart
• Rapid heartbeat
• Irregular heart rhythm
• Coronary artery disease
• Angina (chest pain)
• Reduce the risk of death after a heart attack

Beta-blockers are also approved for other uses unrelated to your heart or blood vessels. These include:

• Essential tremor
  
• Glaucoma
• Migraines (for prevention)

Off-Label Uses

In addition to their Food and Drug Administration (FDA)–approved uses, sometimes beta-blockers are prescribed to treat conditions that differ from what the drug was initially approved to treat. This is called off-label use.

Certain beta-blockers are sometimes used off-label to treat:

• Certain types of anxiety, such as performance anxiety
• Symptoms of overactive thyroid gland (hyperthyroidism) or thyroid storm (life-threatening condition in which the thyroid releases a lot of hormone in a short amount of time)
  

How Do Beta-Blockers Work?

Your body uses chemicals called neurotransmitters to send messages to cells to act a certain way. Adrenaline (also called epinephrine) is an activating neurotransmitter naturally produced by the body.

When activated, adrenaline sends messages to increase heart rate, blood pressure, and the force with which the heart beats.

Beta-blockers attach to sites on cells called receptors that block the action of adrenaline. By blocking adrenaline, beta-blockers reduce heart rate, lower blood pressure, and decrease the force with which your heart pumps blood.

What Are Beta-Receptors and What Do They Do?

To work, beta-blockers must attach to sites throughout your body called beta-receptors. Different types of beta-receptors are located in several areas of your body and have various functions when activated.

Beta-1 Receptors

Beta-1 receptors are typically found in the heart and kidneys. Activating this type of receptor results in:

• Increased heart rate
• Increased heart pumping force
• Release of renin (an enzyme that helps raise blood pressure) from your kidneys

Beta-blockers that target beta-1 receptors help slow heart rate, lower blood pressure, and relieve chest pain.

Beta-2 Receptors

Beta-2 receptors are mainly located in the smooth muscle of your respiratory system, blood vessels, and nervous system.

Beta-blockers that attach to beta-2 receptors in the blood vessels help lower blood pressure by relaxing and widening your blood vessels. Beta-blockers that attach to beta-2 receptors in the nervous system help reduce tremors.

Other medications that target beta-2 receptors in the lungs are typically used to treat breathing conditions, such as asthma and chronic obstructive pulmonary disease (COPD). These drugs are not beta-blockers. Instead, they activate beta-receptors in the lungs.

Beta-3 Receptors

Beta-3 receptors are found in fat cells and your bladder. Activating beta-3 receptors results in fat cell breakdown and relaxation of your bladder. Because activating this receptor may also cause tremors, many medications don't target beta-3 receptors.

Examples of Beta-Blockers

The table below shows examples of commonly prescribed beta-blockers and their uses.

What Are the Side Effects of Beta-Blockers?

As with all medications, beta-blockers may cause side effects in some people.

Side effects may vary based on which beta-blocker you take. But in general, many beta-blockers have similar common side effects. These can include:

• Tiredness
• Dizziness
• Nausea
• Cold hands or feet
• Low blood pressure
• Dry mouth or eyes

In rare cases, beta-blockers may cause serious side effects, such as:

• Depression
• Dangerously slow heart rate
• High blood sugar (hyperglycemia)
• Erectile dysfunction (difficulty getting or keeping an erection)

These lists do not reflect all the potential side effects of beta-blockers. Your healthcare provider can answer questions about side effects specific to your treatment and condition.

Who Shouldn't Take Beta-Blockers?

Beta-blockers may not be for everyone. They may worsen or negatively affect certain health conditions.

Before you start taking a beta-blocker, let your healthcare provider know if:

• You have asthma.
• You have a condition or take medications that may cause low blood sugar level.
• You have Raynaud's phenomenon.
• You have low blood pressure.
• You have a slow heart rate.
• You have certain conditions that affect your heart rhythm.
  

What to Avoid When Taking Beta-Blockers

Some medications may negatively affect beta-blockers. They may increase the risk of side effects from beta-blockers or affect how well they work.

Let your healthcare provider know if you take:

• Certain antidepressants, such as Prozac (fluoxetine), Paxil (paroxetine), and Cymbalta (duloxetine)
• Other medications that affect heart rhythm, such as Pacerone (amiodarone) and Lanoxin (digoxin)
• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Celebrex (celecoxib)
• The antifungal terbinafine oral tablet
• Medications that help lower blood sugar, such as Lantus (insulin glargine) and (Glucotrol XL (glipizide)
• Certain herbs, including Ginkgo (Ginkgo biloba) and Saint-John's-wort

Your healthcare provider can help you decide if beta-blockers are a safe option for you.

In some cases, they may adjust the dose of your beta-blocker or another medication to reduce your risk of side effects. They may also monitor you more closely to check that your medications are working properly.

Advantages and Disadvantages of Beta-Blockers

As with all medications, beta-blockers have benefits and drawbacks.

If your healthcare provider is considering prescribing a beta-blocker, they'll likely discuss some of the drug's advantages and disadvantages with you. Below are a few examples.

Alternatives to Beta-Blockers

While beta-blockers are effective in treating several heart conditions, they may not be right for everyone. If you have a health condition or take other medications that may be negatively affected by beta-blockers, your healthcare provider may recommend alternatives to beta-blockers.

Below are examples of medications your healthcare provider may prescribe instead of beta-blockers. They may also suggest other natural methods and lifestyle changes to help keep your heart healthy.

Drugs That Slow Heart Rate and Lower Blood Pressure

Beta-blockers slow your heart rate and lower blood pressure. The following medications are beta-blocker alternatives that can have the same effects:

• Cardizem (diltiazem)
• Verelan (verapamil)
• Corlanor (ivabradine)

Natural Ways to Lower Your Blood Pressure

Some supplements and herbs are thought to act like beta-blockers. In some studies, they have been found effective in reducing blood pressure or regulating heart rhythm.

However, it's important to remember these drugs should not be used as a substitute for healthy lifestyle changes or medication if necessary.

Examples include:

• Magnesium
• L-arginine
• Potassium
• Omega-3 fatty acids
• Garlic
• Hawthorn
• Red yeast rice

It's important to talk with your healthcare provider before taking any supplements or herbs. Many of them have side effects or interact with other medications. Your pharmacist or provider can let you know if any of these are safe for you to take.

Lifestyle Changes for Healthy Blood Pressure

Even if you take beta-blockers or other medications to help lower your blood pressure or manage your heart condition, you can also implement healthy lifestyle changes to help keep your heart healthy.

The American Heart Association recommends the following lifestyle changes to help with healthy weight loss, which can help lower your blood pressure and reduce your risk of heart-related conditions:

• Limit alcohol consumption.
• Increase physical activity.
• Reduce the amount of sodium in your diet.
• Adopt a heart-healthy food plan, such as the DASH (Dietary Approaches to Stop Hypertension) diet.
  

Summary

Beta-blockers are commonly prescribed to help lower blood pressure and slow down heart rate. Some beta-blockers are also approved to treat other conditions, such as glaucoma and migraine headaches.

Examples of beta-blockers include Toprol XL (metoprolol), Inderal LA (propranolol), and Timoptic (timolol).

Beta-blockers work by attaching to beta-receptors in your body and blocking the action of adrenaline in these sites. Depending on where the receptors are located, the action of beta-blockers can relax your blood vessels, relieve chest pain, or reduce tremors.

Most common side effects of beta-blockers are mild. However, beta-blockers may worsen certain health conditions, including asthma, Raynaud's phenomenon, and depression. They may also interact with some medications, such as NSAIDs and medications for diabetes.

Talk with your healthcare provider if you want to learn more about beta-blockers. They can help you decide whether these drugs are effective and safe for your condition.