Beta Blockers: How They Work, Types, Benefits & Side Effects

According to the Centers for Disease Control and Prevention, a whopping 70 percent of adults over the age of 65 living in the United States take at least one type of heart medication every day. Among the most commonly prescribed types include beta blockers, which are used by millions of Americans to manage a variety of conditions — including high blood pressure, irregular heartbeats and chest pains.

Researchers at Harvard Medical School have referred to beta blockers as “cardiac jacks of all trades.” So what are beta blockers, and what do they do exactly?

These drugs work by blocking receptors in the heart and elsewhere that control blood flow and the release of certain hormones, including adrenaline. Interestingly, beta blockers actually have some similar effects as exercise on the cardiovascular system, including lowering your heart rate (which occurs once you become “exercise-trained”), reducing your blood pressure and even protecting against anxiety.

They are also believed to help save lives, thanks to their ability to reduce recurrent heart attacks.

What Are Beta Blockers?

Beta blockers (BBs) are a type of cardiac medication. In the U.S., these drugs have been approved by the Food and Drug Administration for the treatment of  a number of different conditions, most often those that affect the heart.

Ad

They are often prescribed after someone suffers a heart attack or used to help treat other cardiovascular conditions— such as abnormal heart rhythms (called arrhythmias), abnormally fast heart rates (called tachycardia) and irregular rhythms like atrial fibrillation.

What is the function of a beta blocker? BBs slow down your heart rate and have other effects, such as decreasing blood pressure and chest pains, in part thanks to their ability to mute the effects of adrenaline.

How They Work

These drugs work by blocking beta receptors that are found in the body in three forms:

• Beta-1 (B1) receptors —located primarily in the heart; have the job of mediating cardiac activity.
• Beta-2 (B2) receptors— located in many organ systems, including the lungs and in blood vessels; control various aspects of metabolic activity and induce smooth muscle relaxation.
• Beta-3 (B3) receptors — induce the breakdown of fat cells blocking these betas is believed to be less important for management of diseases than the other two types.

The effects produced by BB drugs depends on the type of receptors that are being blocked. Different types of beta blockers can block receptors in various organs.

Many beta blockers bind to the B1 and B2 receptors, so they inhibit their effects.

Some experts describe beta blockers as “relieving stress on the heart” because they give the heart a break from working and pumping so hard. Here is more about how BB drugs affect the heart, cardiovascular system and other organs:

• As mentioned above, they work by slowing down your heart rate. In other words, the heart beats with less force when it contracts. One reason this happens is due to decreased effects of adrenaline, the hormone that causes the heart to pump faster.
• Beta blockers also reduce blood vessel contractions and blood pressure. This happens when they bind to B1 receptors. They also decrease the demand of the heart muscle for oxygen. The reason for reduced blood pressure is decreased renin release (an enzyme secreted by and stored in the kidneys that promotes the production of the protein angiotensin) and reduced cardiac output.
• BBs can affect the brain and other parts of the body too. They can stop catecholamines, epinephrine (adrenaline) and norepinephrine from binding to B1 receptors. Because these are stimulating “stress hormones,” BBs can have anti-anxiety effects. They basically stop hormones from preparing the body for an emergency (or experiencing a “fight or flight” response).
• Binding to B2 receptors causes relaxation of the smooth muscles and increased metabolic effects, such as glycogenolysis (the breakdown of glycogen).
• BBs can lower the secretion of melatonin, which means they can cause insomnia and trouble sleeping in some people.

Types

There are now more than a dozen beta blockers available (also sometimes called beta-adrenergic blocking agents). They come in three main forms: oral (taken by mouth, including in extended release forms), intravenous (given by injection) and ophthalmic (used to treat the eyes).

Doctors decide which type to prescribe or administer based on a patient’s symptoms and overall health.

What drugs are considered beta blockers? Here is a list of beta blocker drugs, along with their brand names:

• Propranolol (Inderal)
• Metoprolol (Lopressor)
• Atenolol(Tenormin)
• Acebutolol (Sectral)
• Bisoprolol (Zebeta)
• Nadolol (Corgard)
• And other types, such as Betaxolol, Carvedilol, Esmolol, Labetalol and Sotalol

Beta-blockers are classified as either non-selective and beta-1 selective.

• Non-selective types bind to both beta-1 and beta-2 receptors. Examples of this type include propranolol, carvedilol, sotalol and labetalol.
• Beta-1 selective blockers only block beta 1 receptors. These are sometimes called “cardio selective” BBs. Examples of this type include atenolol, bisoprolol, metoprolol and esmolol.

Dosages of BBs range depending on the specific medication and condition that’s being treated.

Benefits/Uses

Beta blockers are considered “essential drugs” and first-line treatments in many acute and chronic conditions.

The most common reasons that beta blockers are prescribed are to help treat/manage:

• Symptoms following a heart attack, such as angina/chest pain (which occurs when the oxygen demand of the heart exceeds the supply) and high blood pressure. Using these drugs may also improve survival after a heart attack has occurred or if someone has congestive heart failure or coronary artery disease
• Irregular heartbeat (arrhythmias)
• Fast heart rates (tachycardia)
• High blood pressure (hypertension)
• Other forms of irregular heart rhythms, like atrial fibrillation
• Hyperthyroidism and hypothyroidism
• Tremors
• Aortic dissection
• Glaucoma
• Migraines
• Long QT syndrome
• Hypertrophic obstructive cardiomyopathy
• Anxiety* (see below, as BBs are not technically approved for this use)

Below is more about the main benefits of BBs:

1. Help Combat Heart Disease and Related Symptoms

In 2013, a study was published in the journal BMC Cardiovascular Disorders that analyzed 30 trials involving patients on BBs. Overall, researchers found that compared to people taking a placebo, those taking BBs experienced a reduced the risk of sudden cardiac death (such as a heart attack), reduced risk of death from other cardiovascular causes and reduced risk of all-cause mortality.

Ad

BBs can also help people with heart conditions such as angina and abnormal heart rhythms feel better.

That said, a large Cochrane Review discovered evidence that “beta-blockers were not as good at preventing the number of deaths, strokes, and heart attacks as other classes of medicines such as diuretics, calcium-channel blockers, and renin-angiotensin system inhibitors.”

2. Inexpensive and Generally Safe

Although beta blocker side effects are somewhat common, they are usually just “annoying” and not serious or life-threatening in most cases. These medications are widely available, inexpensive (and often come in generic forms) and have been used since the 1960s by millions of people.

3. May Help Reduce Anxiety and Tremors

While the FDA has not approved the use of beta blockers for anxiety or phobias, some people use them “off label” for their strong anxiolytic (anti-anxiety) effects.

They can decrease nervousness/anxiety symptoms due to their ability to inhibit activity of the sympathetic nervous system and block adrenaline, which normally leads to a “fight or flight” response. They are even used by performers and athletes in some cases to improve performance due to their anti-tremor and calming effects.

Risks and Side Effects

What are the most common side effects of beta blockers? It’s possible for beta blockers side effects to include:

• Bradycardia (slowed heart rate) and hypotension (low blood pressure), considered to be the two most common adverse effects
• Fatigue
• Dizziness
• Nausea
• Constipation
• Weight gain
• Sexual dysfunction and erectile dysfunction
• Insomnia, sleep changes and nightmares
• A slight rise in triglyceride levels
• Among people with a history of asthma, bronchospasms and trouble breathing
• Among people with hypoglycemia, tachycardia
• Edema
• Possibly a higher risk for complications, such as heart attacks, when stopping use

It’s been found that most people who take a beta blocker experience at least one side effect, and many have to switch drugs in order to keep these effects under control.

In order to prevent complications and side effects, some patients are monitored to ensure that their heart rates and blood pressure remain within the normal range. BBs also should be prescribed initially at low doses and then gradually increased over the course of several weeks until an effective dose is established.

Additionally, it’s important to wean off these drugs slowly, as an abrupt ending can potentially lead to reactions like a heart attack, stroke or erratic heart rhythm.

Is it safe to combine beta blockers and exercise? According to the American Heart Association, this depends on the severity of someone’s condition.

People should play it safe and check with their health care providers before starting a new exercise program if taking these drugs.

Is there such thing as natural beta blockers that you can try instead?

If you’re using BB drugs to improve heart health and blood pressure, then making dietary and lifestyle changes can likely help (although you may still require medication). Some things to focus on in order to support cardiovascular health include:

• Eating a diet rich in high-antioxidant foods, especially vegetables, fruits, herbs, spices and teas. Some of the best foods to lower blood pressure naturally include pomegranate and tart cherry juice, greens like spinach, nuts like pistachios, beetroot juice, olive oil, garlic, dark chocolate, and flaxseeds.
• Consuming enough potassium-rich foods, such as sweet potatoes, bananas, avocados, greens and organic dairy products.
• Exercising regularly.
• Managing stress and getting enough sleep.
• Possibly taking herbs and supplements, such as magnesium, omega-3s, CoQ10, hawthorn and barberry.

Drug Interactions

Are beta blockers safe for people who take other medications? Beta blockers should not be used in patients with:

• Hypotension (low blood pressure)
• Bradycardia (a very slow heartbeat)
• Asthma and obstructive pulmonary disease, depending on the specific drug. For many years, BBs were considered contraindicated in asthmatic patients, however today certain types of cardio-selective drugs may be prescribed safely
• Cocaine-induced coronary vasospasm
• Acute or chronic bradycardia and/or hypotension
• Torsades de pointes (a specific type of abnormal heart rhythm that can lead to sudden cardiac death)
• Raynaud phenomenon
• Severe diabetes

It’s important to be careful when combining different cardiovascular drugs, since this can lead to side effects like very low blood pressure. If you take medication in addition to beta blockers to manage your blood pressure, such as alpha blockers and calcium channel blockers, make sure you are working carefully with your doctor and being monitored.

Is it dangerous to combine beta blockers and alcohol? Because both beta blockers and alcohol can lower your blood pressure, it may not be safe to combine these two.

Speak with your doctor about the potential risks involved, which will depend on the dose and type of BB that you take.

Conclusion

• What are beta blockers? BBs are a group of cardiac medications. They work by blocking beta receptors located in the heart and other organs.
• Benefits and uses of BBs can include treating/managing conditions like heart disease, history of a heart attack, high blood pressure, irregular heart beats, tremors, migraines and anxiety.
• Beta blockers side effects can include low blood pressure, slowed heart rate, fatigue, digestive issues, trouble sleeping and more.