The Ultimate Guide to Beta Blockers

Doctors and nurse practitioners prescribe beta blockers, also known as beta-adrenergic blocking agents, to tens of millions of American patients. Some patients have little knowledge about what these medications are meant to accomplish. This ultimate guide to beta blockers describes this life-saving medicine with more than 25 years of widespread and generally safe use. This guide also cautions readers about side effects and controversies concerning beta blockers.

Beta BlockerHow do beta blockers work?

Beta blockers are medications intended to block norepinephrine and epinephrine (adrenaline) from binding to beta receptors on nerves. The medication can slow nerve impulses that travel through your heart, controlling heart rate and the strength of your heartbeat. Beta blockers also can open (dilate) blood vessels to improve blood flow and may constrict air passages by stimulating the muscles surrounding air passages to contract.

Doctors may prescribe beta-blockers to treat high blood pressure (hypertension), congestive heart failure (CHF), abnormal heart rhythms (arrhythmias) and chest pain (angina). Heart attack patients also may receive beta blockers to prevent future heart attacks and some patients may receive beta blockers to prevent migraines. Other uses include the treatment of hyperthyroidism, akathisia (restlessness), and anxiety. Some beta blockers reduce the production of aqueous humor in the eye and therefore are used for reducing pressure in the eye caused by glaucoma.

The type of beta blocker prescribed depends upon the patient’s needs. The body contains 2 main beta receptors called beta 1 (ß1) and beta 2 (ß2). Beta 1 receptors are responsible for the heart rate and strength of the heart beat. Beta 2 receptors are responsible for smooth muscle function, or for control over the muscles that control body functions that you have no control over.

HeartBeta blocker functions

Three different types of beta receptors control several functions, based upon their location within the body:

  1. Beta-1 (ß1) receptors are located in the heart, eye, and kidneys;
  2. Beta (ß2) receptors are found in the lungs, gastrointestinal tract, liver, uterus, blood vessels, and skeletal muscle; and
  3. Beta (ß3) receptors are located in fat cells.

Selective beta blockers block beta 1 receptors more than they block beta 2 receptors, but some selective beta blockers block both receptors. Nonselective beta-blockers block both beta 1 and beta 2 receptors. Some beta blockers have intrinsic sympathomimetic activity (ISA), which means they actually increase blood pressure and heart rate. Some beta blockers block beta and alpha-1 receptors, adding to the blood dilating effect of other medications.

Beta blockers aren’t usually prescribed until other blood pressure medications, such as diuretics, haven’t worked effectively. Beta blockers with brand names include acebutolol (Sectral), atenolol (Tenormin), bisoprolol (Zebeta), metoprolol (Lopressor or Metoprolol), nadolol (Corgard), and timolol (Blocadren or Timolol Oral).

HallucinationsAdverse effects

Practically any medication may present side effects for patients, and beta blockers are no exception. The following lists contain reported side effects that are common, central nervous system side effects and less common or rare side effects. Patients should report any side effects to their physician.

Common side effects of beta blockers may include:

  • Cold hands and/or feet
  • Weakness
  • Dry mouth, eyes and skin
  • Fatigue or drowsiness

Central nervous system effects of beta blockers may include:

  • Headache
  • Depression
  • Confusion
  • Dizziness
  • Nightmares and/or hallucinations

Less common or rare side effects may include:

  • Shortness of breath or wheezing
  • Trouble sleeping
  • Loss of sex drive or impotence
  • Depression
  • Diarrhea or constipation
  • Stomach or muscle cramps
  • Nausea and/or vomiting
  • Rash
  • Blurred vision
  • Slow heartbeat or low blood pressure
  • Swelling of hands and/or feet
  • Back or joint pain
  • Sore throat

Beta blockers generally aren’t used in people with asthma. Beta blockers may trigger severe asthma attacks, especially those medications that block ß2 receptors. Beta blockers may block signs of low blood sugar for diabetics, such as rapid heart beat. It’s important to monitor blood sugar on a regular basis.

Since beta blockers can slow heart rate and reduce blood pressure, they may cause heart failure or heart block in patients with heart problems.

Beta blockers also may affect cholesterol and triglyceride levels, causing a slight increase in triglycerides and a modest decrease in high-density lipoprotein, the “good” cholesterol. These changes often are temporary.

You should never abruptly stop taking a beta blocker because doing so could increase your risk of angina, heart attack or sudden death. Only reduce your medication under a doctor’s orders, according to a plan to withdraw the medication.

EmphysemaMedical Interactions

Other medicines that you may be taking can increase or decrease the effect of beta-blockers. These effects are called “interactions.” Be sure to tell your doctor about every medicine and vitamin or herbal supplement that you currently take, so he or she can make you aware of any interactions.

The following medicinal categories contain items that can increase or decrease the effects of beta-blockers. Because there are so many kinds of medicines within each category, not every type of medicine is listed.

  • Certain anti-depressants
  • Allergy shots or medications
  • Diabetes medicines, including oral medicines and insulin
  • Medicines to treat asthma, chronic bronchitis, and emphysema
  • Medicines to treat coughs and colds
  • Medicines to treat indigestion
  • Other medicines used to treat high blood pressure. These other medicines may increase beta-blocker effects.

Talk with your doctor about eating or drinking products that contain caffeine. Other over-the-counter medications also need discussion, such as pills or syrups that treat coughs and colds, antihistamines and antacids that contain aluminum. You should also avoid drinking alcohol, because alcohol could decrease beta blocker effects.

PhysicianTell your doctor…

Talk to your doctor about your medical history before you start taking beta-blockers to help increase the benefits of taking beta blockers and to reduce your risks. Other than discussion about current medications, be sure to discuss the following items:

  • If you are pregnant, plan to become pregnant or if you are breast-feeding.
  • Individuals over age 60 have more problems while taking beta blockers than younger individuals.
  • If you have had a heart attack or other heart disease or if you experience poor circulation in your hands and feet.
  • If you have bradycardia (slow heart rate) or a heart block.
  • If you have asthma, as beta blockers may worsen your condition.
  • Individuals who suffer from hay fever, chronic bronchitis or emphysema may experience worse symptoms on beta blockers.
  • Diabetics and people who suffer from hypoglycemia should be aware that beta blockers may disguise low blood sugar symptoms.
  • If you have an overactive thyroid, kidney or liver disease.
  • If you suffer from allergies, especially to foods or dyes. Beta blockers may worsen allergic reactions.
  • Before having surgery, tell the doctor or dentist in charge that you are taking a beta-blocker.

Other Advice

  • If you miss a dose of your beta blocker, take it as soon as you remember, but not if it is within four (4) hours of your next dose (8 hours for penbutolol, atenolol, nadolol). If it is, skip the missed dose and resume your usual dosing schedule. Do not “double-up” the dose to catch up. If you have doubts about your missed dose, call your doctor or nurse practitioner.
  • Store your beta blocker at room temperature (between 59-86 degrees F, or 14 and 30 degrees C) away from moisture (not in a bathroom cabinet) and sunlight (not on a windowsill).
  • Keep emergency numbers for your doctor, hospital or emergency services close at hand to use if you experience any side effects or illness.
  • Many beta blockers are available as low-cost generics. Learn more about how to keep your beta blocker medical costs down through this Consumer Reports article.
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