Beta-Blockers for High Blood Pressure

Medically Reviewed by Jabeen Begum, MD on April 05, 2024
9 min read

Beta-blockers (also called beta-adrenergic blockers) are drugs that are used to lower blood pressure (among other things). They do this by blocking the effects of the hormones adrenaline and noradrenaline in your cardiovascular system (your heart and blood vessels).

Adrenaline triggers your body's fight-or-flight response. Noradrenaline works with adrenaline to increase your heart rate and the amount of blood that your heart is pumping to help you get ready to fight or flee if you're attacked. When you block the effects of these hormones with beta-blockers, your heart rate slows, the force your heart uses to pump blood through your body eases, and your blood vessels relax. So, your heart doesn't work as hard and your blood pressure goes down.

Your doctor may want you to try another medicine (such as a diuretic or water pill) to control your blood pressure before you try a beta-blocker.

Beta-blockers prescribed for high blood pressure include:

Many people need to take a combination of a couple of different kinds of medicines (such as a beta-blocker and a calcium channel blocker) to control their high blood pressure. This is because your body uses a few different ways of controlling your blood pressure. So, it works better when you take a combination of medicines that work in different ways.

These medicines block the actions of stress hormones to help your heart beat more slowly and with less force. They also open up your blood vessels to improve blood flow and lower your blood pressure.

Beta-blockers mechanism of action

Your body makes two hormones that control your body's stress response: adrenaline (also called epinephrine) and noradrenaline (norepinephrine). Your stress response gets your body ready to fight or run if you're threatened. However, your body can also release these hormones as you go through the stress of everyday life. So, you may have constant high levels of adrenaline and noradrenaline in your system.

Adrenaline and noradrenaline trigger your stress response in part by binding to proteins called receptors on the surface of cells in your heart, blood vessels, and muscles. When adrenaline and noradrenaline bind with a receptor, they trigger the cell to behave a certain way.

There are a few different types of receptors, but the ones that beta-blockers work on are the beta receptors: beta-1 (B1), beta-2 (B2), and beta-3 (B3). B1 receptors are mainly on the cells of your heart and kidneys. When they are activated in your heart, they increase your heart rate and the force with which your heart pumps blood. When they are activated in your kidneys, they release an enzyme called renin into your bloodstream.

B2 receptors are mainly in the tissues of your respiratory system (such as your windpipe and airway tubes), blood vessels, and nervous system. When they're activated, they do the following:

  • Relax your blood vessels and your airway tubes, so your blood pressure drops and you can breathe more easily
  • Activate your liver to turn glycogen (sugar stored in your liver for fast energy) into glucose so your body can use it
  • Increase your heart rate and pumping force
  • Cause muscle tremors

B3 receptors are mainly in your fat cells and bladder. When they are activated, your fat cells break down, your bladder relaxes, and your muscles shake slightly (tremor).

Beta-blockers keep adrenaline and noradrenaline from binding to these receptors. Among other things, this keeps your heart rhythm slow and your blood vessels wide, which eases the strain on your heart and lowers your blood pressure.

Doctors prescribe beta-blockers to treat not only high blood pressure but also heart failure, anxiety, irregular heart rhythms, and other conditions.

Beta-blockers for anxiety

You may get anxiety because your stress response is triggered in certain situations, for instance before you give a talk in front of other people. Studies show that beta-blockers can help ease the symptoms of anxiety, such as sweating, shaking, and heart racing.

However, beta-blockers aren't FDA-approved to treat anxiety. Sometimes doctors prescribe them "off-label," which means the drug hasn't been specifically approved to treat that condition. However, they may still prescribe it for other conditions if there's evidence that it could help in those cases.

Beta-blockers seem to be most effective for people who have anxiety in certain situations rather than generalized anxiety. They don't treat the cause of your anxiety. They only relieve the symptoms.

Beta-blockers for heart failure

When you have heart failure, your heart can't pump enough blood to meet your body's needs for blood and oxygen. Beta-blockers slow your heart rate and open your blood vessels so your heart doesn't have to work as hard. This reduces your symptoms, keeps you out of the hospital, and helps you live a longer, fuller life.

Beta-blockers for atrial fibrillation

Atrial fibrillation (AFib) is an irregular and often very fast heart rhythm (arrhythmia). It happens when the upper chambers (atria) of your heart get out of sync with the lower chambers (ventricles). Because your blood doesn't flow as smoothly, AFib can cause symptoms such as shortness of breath and dizziness, and it can also cause your blood to clot and increase your risk for stroke. Beta-blockers slow your heart rate so the heart chambers can get back in sync. They prevent symptoms such as tiredness and heart palpitations.

Beta-blockers for postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome (POTS) makes your heart speed up when you go from sitting or lying down to standing up. It happens when your body can't keep your blood pressure steady because it's having trouble balancing your heart rate and how hard your heart squeezes to pump blood. As is the case with anxiety, beta-blockers aren't FDA-approved to treat POTS, but they may help some of your symptoms. So, your doctor may try a low dose to help slow your heart rate when you stand up.

Beta-blockers for migraines

Migraines are severe, throbbing headaches, usually on just one side of your head. Doctors aren't exactly sure why some people get migraines, but part of the reason may be that the blood vessels in your brain open up, which causes pressure that you feel as a headache. Some beta-blockers, such as propranolol and metoprolol, may prevent migraine attacks, lessen the severity of an attack, or shorten them by keeping the blood vessels in your brain from opening up as wide and calming your nervous system.

Other uses for beta-blockers

Beta-blockers also have FDA approval for a few other conditions, including:

  • Aortic dissection, which is a tear in the main artery (aorta) that leads to your heart
  • Chest pain (angina)
  • Coronary artery disease
  • Glaucoma, which is high pressure in your eye
  • Heart attack
  • Portal hypertension, which is high pressure in the blood vessel that goes to your liver
  • Involuntary, rhythmic shaking, especially in your hands (essential tremor)

Beta-blockers keep adrenaline and noradrenaline from binding to the beta receptors on the cells in your heart, blood vessels, lungs, digestive tract, liver, and fat cells. There are three types of beta receptors:

  • B1 receptors are mainly in your heart and help control your heartbeat.
  • B2 receptors are in your lungs, digestive tract, liver, and blood vessels. They help control your body's energy use (metabolism) and muscles.
  • B3 receptors are in your fat cells, and they help break down your fat cells when you need energy.

Different beta-blockers bind to these three receptors differently. For instance, some are called nonselective, which means they bind to both B1 and B2 receptors about the same. These include:

  • Carvedilol
  • Labetalol
  • Propranolol
  • Sotalol

Other beta-blockers bind only to B1 receptors. Doctors call these "cardio-selective" because B1 receptors are almost all in your heart. Examples of these include:

  • Atenolol
  • Bisoprolol
  • Esmolol (only used in hospitals because you take it by IV)
  • Metoprolol

Some beta-blockers bind selectively to B2 and B3, but doctors don't prescribe these because studies on them so far haven't shown that they can reduce symptoms for any of the conditions.

Some beta-blockers also bind to other receptors called alpha receptors, specifically the alpha-1 receptor. Many of these bind to B1 and B2 as well as alpha-1. These types seem to be very helpful for treating high blood pressure because they have a double effect. Examples of these include:

  • Bucindolol
  • Carvedilol
  • Labetalol

Beta-blockers are categorized into three generations based on when they were developed and the receptors they bind with. They are:

First-generation beta-blockers. These were developed in the early 1960s. They are nonselective and bind to both B1 and B2 receptors.

Second-generation beta-blockers. These were developed in the late 1960s. They are selective because they mainly bind to B1 receptors.

Third-generation beta-blockers. These were developed in the mid-1970s. These tend to bind to alpha-1 receptors and either B1 or B2 receptors. These tend to work really well for high blood pressure because they can have double the effect.

Because of their effects on your heart and blood vessels, beta-blockers can cause side effects, such as:

  • Slow heart rate
  • Low blood pressure
  • Irregular heart rhythms
  • Dizziness
  • Tiredness
  • Nausea
  • Constipation
  • Trouble getting an erection

Don't drive or use heavy machines until you know if these drugs make you dizzy. The dizziness should stop after you've been on beta-blockers for a few days.

Let your doctor know if you have side effects from your beta-blocker. They may want to change your dose or switch you to a different medicine.

Some beta-blockers may also cause:

  • Trouble sleeping or changes in your sleep patterns
  • Nightmares
  • Weight gain

Beta-blockers can make some conditions worse. Talk to your doctor if you have one of the following:

  • Asthma
  • Low blood sugar (hypoglycemia)
  • Long QT syndrome (a problem with your heart's electrical system)
  • Raynaud's syndrome (reduced blood flow in the hands and feet)

If you have diabetes, a beta-blocker can hide signs of low blood sugar. You may need to check your blood sugar levels more often.

Older beta-blockers such as propranolol and metoprolol may raise your triglycerides and lower your "good" HDL cholesterol slightly. Newer medicines such as nebivolol and carvedilol are less likely to have this effect. Smokers are more likely to have it.

Don't stop taking your medicine unless your doctor says so. If you stop them suddenly or without your doctor knowing, it can increase your chance of a heart attack or other heart problems.

Beta-blockers may change the way your other medicines work, or your other medicines can change how your beta-blocker works. Tell your doctor about every over-the-counter and prescription medicine, vitamin, and supplement you take before you start a beta-blocker.

Beta-blockers can affect many common medicines. Some of the classes of medicines that interact with beta-blockers include:

  • Medicines for irregular heart rhythms
  • Other blood pressure medicines
  • Some antidepressants
  • Allergy shots
  • Insulin and other diabetes medicines
  • Medicines to treat asthma, chronic bronchitis, emphysema, and chronic obstructive pulmonary disease (COPD)

Avoid the following when taking beta-blockers:

  • Caffeine
  • Alcohol
  • Over-the-counter cough and cold medicines
  • Over-the-counter antihistamines
  • Antacids containing aluminum

Your doctor may not prescribe beta-blockers if you have:

Asthma or another lung disease, especially for people with moderate to severe cases. For instance, first-generation or nonselective beta-blockers can cause an asthma attack or trouble breathing if you smoke, have asthma, or other lung conditions. If you have mild asthma or lung disease, your doctor may try a selective beta-blocker, but they will usually avoid using them in people with moderate to severe cases.

Certain heart rhythm problems (arrhythmia). Beta-blockers can make some arrhythmias worse.

Low blood pressure (hypotension) or slow heart rate. Beta-blockers lower your blood pressure and slow your heart rate, so if you already have these problems, they can make your condition worse.

Raynaud's phenomenon. Raynaud's can cause low blood circulation in your hands and feet, and beta-blockers can make this worse.

Low blood sugar (hypoglycemia). These drugs can hide symptoms of low blood sugar. You'll have to check your blood sugar more often when you have diabete s, especially if you have type 1 diabetes.

Uncontrolled heart failure.

Pregnancy. Beta-blockers may cause your baby to develop heart defects if you take them during pregnancy. Tell your doctor right away if you get pregnant while you're taking a beta-blocker.

Beta-blockers lower your blood pressure and treat conditions such as heart failure, angina, and migraine. Some only work on your heart, while some affect other parts of your body. These drugs can cause side effects such as a slow heart rate and dizziness. They may not be safe for people with asthma, an already slow heart rate, or low blood pressure.