beta-blocker

beta-blocker or beta-adrenergic blocking agent (bāˈtə ădˌrənûrˈjĭk) [key], drug that reduces the symptoms connected with hypertension, cardiac arrhythmias, angina pectoris, migraine headaches, and other disorders related to the sympathetic nervous system. Beta-blockers also are sometimes given after heart attacks to stabilize the heartbeat. Within the sympathetic nervous system, beta-adrenergic receptors are located mainly in the heart, lungs, kidneys, and blood vessels. Beta-blockers compete with the nerve-stimulating hormone epinephrine for these receptor sites and thus interfere with the action of epinephrine, lowering blood pressure and heart rate, stopping arrhythmias, and preventing migraine headaches. Because it is also epinephrine that prepares the body for "fight or flight" in stressful or fearful situations, beta-blockers are sometimes used as antianxiety drugs, especially for stage fright and the like. People taking a beta-blocker must avoid caffeine, alcohol, and salty foods, because the interaction of those substances and the drug can raise the heart rate and blood pressure. Propranolol (Inderal) is a commonly used beta-blocker.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on beta-blocker from Fact Monster:

  • antianxiety drug - antianxiety drug antianxiety drug, drug administered for the relief of anxiety. Although their ...
  • migraine - migraine migraine , headache characterized by recurrent attacks of severe pain, usually on one side ...
  • fainting - fainting fainting or syncope, temporary loss of consciousness caused by an insufficient supply of ...
  • drugs - drugs drugs, substances used in medicine either externally or internally for curing, alleviating, ...
  • hypertension - hypertension hypertension or high blood pressure,elevated blood pressure resulting from an increase ...

See more Encyclopedia articles on: Pharmacology