Medical Author: Melissa Stöppler, MD
Medical Editor: William C. Shiel, Jr., MD, FACP, FACR
Beta blockers are a common class of prescription drugs that counteract the stimulatory effects of adrenaline (epinephrine) on what are called the beta receptors. These receptors are found in many tissues of the body including the nervous system and heart. When beta receptors are stimulated, the heart beats faster and harder and the blood vessels constrict, resulting in an elevation of blood pressure. If the coronary arteries are narrowed by atherosclerosis, the increased burden on the heart can cause inadequate oxygen delivery to the heart muscle (myocardium) itself, leading to the chest pain and other symptoms of angina pectoris.
Beta blockers act by suppressing these stimulatory impulses and lead to a slowing of the pulse rate and a reduction in blood pressure. By reducing the workload of the heart, they can also relieve symptoms of angina pectoris.
Beta blockers are prescribed as treatments for high blood pressure and have been shown to improve survival when administered following a heart attack.
Since beta blockers can slow the passage of impulses through the heart, these drugs can also be useful for the treatment of cardiac arrhythmias, particularly those involving abnormally fast heart rates or premature beats of the heart. Beta blockers have also been used in the treatment migraine, glaucoma, social anxiety. Certain types of tremors and some cases of mitral valve prolapse can also be treated with beta blockers.
The most common side effects of beta blockers are drowsiness and fatigue, along with dizziness and weakness. Dryness of the mouth, eyes, and skin may occur, and those taking beta blockers may develop cold hands and feet. Sleep disturbances and a decreased sex drive are less common but possible side effects of beta blockers. Wheezing is also a less common but potentially significant side effect of beta blockers, and for this reason, they are often not prescribed for people with asthma. Other serious side effects are rare.
Common beta blockers include acebutolol (Sectral), atenolol (Tenormin), bisoprolol (Zebeta), metoprolol (Lopressor), nadolol (Corgard), and timolol (Blocadren), nebivolol (Bystolic). Some beta blockers are also available in combination with a diuretic.