What Are Beta-Blockers?

Beta-blockers are a group of medicines approved by the U.S. Food and Drug Administration (FDA) to treat a variety of conditions. They are used to lower both blood pressure (hypertension) and heart rate (tachycardia). They are also used to treat those who have had a heart attack (myocardial infarction) or are suffering from heart failure, a condition where the heart isn’t able to pump blood effectively.

Patients with irregular heart rhythms, or arrhythmias, and coronary artery disease can also benefit from beta-blockers. Some people may also be prescribed this medication to manage overactive thyroid (hyperthyroidism), aortic dissection (a medical emergency in which a tear in the aorta occurs), portal hypertension, and glaucoma.

Beta-blockers may also be used to treat other conditions, including:

• Chest pain
• Migraines
• Anxiety disorders
• Tremors
• Cardiomyopathy (enlarged heart)

How Do Beta-Blockers Work?

Beta-blockers work by attaching themselves to receptors in the heart and blood vessels. When this happens, the heart’s ability to beat quickly and forcefully is reduced. As a result the heart pumps less blood with each beat, which lowers blood pressure. They also help open up blood vessels to improve blood flow. These medications do this by affecting substances in the body like renin, a hormone known to raise blood pressure. When levels of substances like renin are reduced, the blood vessels become relaxed, and the overall workload of the heart declines. The heart requires less oxygen when its workload is reduced, which can in turn reduce symptoms like chest pain.

Beta-blockers also manage irregular heart rhythms by extending the time between each heartbeat, giving the heart more time to fill with blood.

Some types of beta-blockers mainly affect the heart. Others affect both the heart and blood vessels.

Common Beta-Blockers

Some commonly prescribed beta-blockers include:

• Sectral (acebutolol)
• Tenormin (atenolol)
• Kerlone (betaxolol)
• Zebeta and Ziac (bisoprolol)
• Coreg (carvedilol)
• Normodyne and Trandate (labetalol)
• Lopressor and Toprol-XL (metoprolol)
• Corgard (nadolol)
• Bystolic (nebivolol)
• Levatol (penbutolol)
• Visken (pindolol)
• Inderal and Inderal LA (propranolol)
• Blocadren (timolol)

Side Effects of Beta-Blockers

Common side effects of beta-blockers include:

• Dizziness
• Weakness
• Drowsiness or fatigue
• Slow heartbeat
• Dry mouth, skin, or eyes
• Headache
• Upset stomach
• Diarrhea or constipation
• Sexual and erectile dysfunction
• Depression
• Heart block

Less-common side effects include:

• Shortness of breath
• Wheezing or trouble breathing
• High blood sugar (hyperglycemia)
• Trouble sleeping
• Swelling of the hands or feet (edema)

Beta-Blocker Precautions

Beta-blockers may not be as effective when taken alongside other medications. Consult a healthcare provider about current medications to prevent any issues, even if the medications are over-the-counter or supplements.

If you have asthma or diabetes, talk to your doctor before taking a beta-blocker. These drugs may trigger a severe asthma attack and can mask signs of low blood sugar.

Let your doctor know about all other medical conditions you have before you start on a beta-blocker. Also, tell your doctor about all medicines you're taking, especially:

• Other medications for high blood pressure
• Antidepressants
• Drugs for diabetes (including insulin)
• Medications for asthma, chronic bronchitis, emphysema, or chronic obstructive pulmonary disease (COPD)
• Allergy shots
• Antacids that contain aluminum
• Over-the-counter (OTC) cough, cold, or allergy medicines

Beta-Blockers, Alcohol, and Caffeine

Avoid eating or drinking products that contain alcohol, which can speed up or slow down the metabolism of certain medications and alter the effect of a medication, or caffeine, also known to affect how beta-blockers work in your body.

Beta-Blockers and Pregnancy

Tell your doctor if you're pregnant, or might become pregnant, while taking a beta-blocker.

Some beta-blockers may be safe to take during pregnancy, while others may be harmful. Research in this area is limited; but the literature suggests the use of beta-blockers during early pregnancy do not increase the risk of congenital or heart malformations. Discuss the risks and benefits of taking these drugs with your doctor. Also, talk to your healthcare provider before taking a beta-blocker if you're breastfeeding.

Beta-Blockers and Certain Populations

Beta-blockers may not work as well in people of African descent as in other racial or ethnic groups. The Joint National Commission recommends other blood pressure medications such as a thiazide diuretic or calcium channel blocker as a first line of treatment for this group. Discuss this more with your doctor.

Consult with your doctor if you have asthma, a slow heart rate, low blood pressure, or Raynaud's phenomenon. Beta-blockers may not be recommended as a first line of treatment when these conditions are present.