How does Beta-Blocker Drugs Work?

Beta-blockers are drugs that can lower stress on the heart and blood vessels by blocking the action of adrenaline. Also, they can help manage migraine, anxiety, tremors, and other conditions.

Beta-blockers work by blocking the action of certain hormones in the nervous system, such as adrenaline. By doing this, they help prevent the activation of the “fight-or-flight” stress response.

In fact, adrenaline and noradrenaline are hormones that prepare the muscles in the body for exertion. Therefore, this is a crucial part of responding to danger.

However, if the body releases high levels of adrenaline, a person may experience a rapid heartbeat, high blood pressure, excessive sweating (Hyperhidrosis), anxiety, and heart palpitations.

Also, blocking the release of these hormones lowers stress on the heart and reduces the force of the heart muscle contractions. Consecutively, it also takes pressure off the blood vessels in the heart, the brain, and body.

Moreover, beta-blockers also obstruct the production of angiotensin II, which is a hormone that the kidneys produce. This relaxes and widens the blood vessels, easing the blood flow through them.

Uses of Beta-Blockers

Migraine

According to the National Library of Medicine (NLM), a type of beta-blocker called propranolol is the most effective first-line therapy for preventing migraine.

In fact, a 2019 review of trials from around the world concluded that propranolol was more effective than a placebo in preventing migraine.

Moreover, the overall results suggested that this medication can reduce the number of episodes a person experiences from five to three per month.

Glaucoma

Glaucoma is a condition in which pressure grows within the eye due to fluid buildup.

Therefore, doctors may prescribe eye drops containing beta-blockers, called Timolol eye drops, to lower the production of this fluid and reduce pressure within the eye.

Anxiety

Beta-blockers block the effects of stress hormones. Accordingly, they can also reduce the physical symptoms of anxiety, such as trembling and sweating.

Although they do not have approval from the Food and Drug Administration (FDA) for treating anxiety, doctors may prescribe them off-label for this purpose.

However, beta-blockers cannot treat anxiety itself. Other treatments, such as counseling, can help address the underlying causes of anxiety.

Overactive Thyroid

Beta-blockers can reduce symptoms such as tremors and a rapid heart rate in people with an overactive thyroid.

Besides, they do this by blocking the action of thyroid hormone in the bloodstream.

Essential Tremor

Beta-blockers such as propranolol, primidone, and topiramate can help manage essential tremor, and are the first-line treatment as recommended by the FDA.

Also, a doctor may recommend using this medication as needed or all the time, depending on a person’s situation.

Types and Brands of Beta-Blockers

Beta-blockers help manage various conditions by blocking beta receptors, which occur throughout the body.

There are three types of beta receptors:

• Beta-1 (B1) receptors, which occur mainly in the heart and regulate cardiac activity
• Beta-2 (B2) receptors, which occur in various organs and play a role in smooth muscle relaxation and metabolic activity
• Beta-3 (B3) receptors, which help break down fat cells

In fact, current medical applications focus on B1 and B2 receptors.

Also, beta-blockers can also be selective or non-selective. Selective beta-blockers mostly target the heart, while non-selective ones manage symptoms in other parts of the body.

Here are some common types and brands of beta-blockers:

• Acebutolol (Sectral)
• Atenolol (Tenormin)
• Betaxolol (Kerlone)
• Bisoprolol/hydrochlorothiazide (Ziac)
• Bisoprolol (Zebeta)
• Metoprolol (Lopressor, Toprol XL)
• Nadolol (Corgard)
• Propranolol (Inderal)
• Sotalol (Betapace)
• Carvedilol(Coreg)

Beta-blockers affect receptors throughout the body and can have a range of side effects, including:

• Abdominal discomfort
• Confusion
• Constipation
• Erectile dysfunction
• Slow heartbeat, or bradycardia
• Fatigue
• Low blood pressure (Hypotension)
• Cold feet and hands
• Memory loss
• Nausea and vomiting
• Sleeping difficulties and disturbances
• Fluid retention, or edema, which may occur when a person starts using carvedilol
• Weakness and dizziness

However, patients with Raynaud’s disease or asthma may have more pronounced side effects.

Also, there is a risk of heart block, especially in people with heart disease.

People should advise their doctor if they have a history of any of the following before taking beta-blockers:

• Asthma, though some types may be suitable
• Bronchospasm
• Severe peripheral artery disease, including Raynaud’s disease
• A slow heart rate
• Uncontrolled heart failure

Also, people with stable heart failure can use beta-blockers.

Patients who have a heart condition or chest pain and a history of cocaine use should talk with their doctor before using beta-blockers. However, this is because there is some debate about whether or not it is safe to use them in these circumstances.

In fact, people with diabetes, especially hypoglycemia, should monitor their blood sugar regularly. In addition, beta-blockers can obstruct signs of low blood sugar, such as a rapid heartbeat.

Moreover, some types of beta-blockers may be safe to use during pregnancy if a doctor advises it. Accordingly, the doctor can advise on which beta-blockers are suitable for an individual to use after considering their full medical history.

Interactions with Other Medications