beta-blocker

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beta-blocker

or

beta-adrenergic blocking agent

(bā`tə ăd'rənûr`jĭk), drug that reduces the symptoms connected with hypertensionhypertension
or high blood pressure,
elevated blood pressure resulting from an increase in the amount of blood pumped by the heart or from increased resistance to the flow of blood through the small arterial blood vessels (arterioles).
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, cardiac arrhythmiasarrhythmia
, disturbance in the rate or rhythm of the heartbeat. Various arrhythmias can be symptoms of serious heart disorders; however, they are usually of no medical significance except in the presence of additional symptoms.
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, angina pectorisangina pectoris
, condition characterized by chest pain that occurs when the muscles of the heart receive an insufficient supply of oxygen. This results when the arteries that supply the heart muscle with oxygenated blood are narrowed by arteriosclerosis.
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, migrainemigraine
, headache characterized by recurrent attacks of severe pain, usually on one side of the head. It may be preceded by flashes or spots before the eyes or a ringing in the ears, and accompanied by double vision, nausea, vomiting, or dizziness.
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 headaches, and other disorders related to the sympathetic nervous systemnervous system,
network of specialized tissue that controls actions and reactions of the body and its adjustment to the environment. Virtually all members of the animal kingdom have at least a rudimentary nervous system.
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. 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 epinephrineepinephrine
, hormone important to the body's metabolism, also known as adrenaline. Epinephrine, a catecholamine, together with norepinephrine, is secreted principally by the medulla of the adrenal gland.
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 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 drugsantianxiety drug,
drug administered for the relief of anxiety. Although their action is not fully understood, most antianxiety medications appear to affect the action of neurotransmitters in the brain (see serotonin and norepinephrine).
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, 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.

beta-blocker

Medicine any of a class of drugs, such as propranolol, that inhibit the activity of the nerves that are stimulated by adrenaline; they therefore decrease the contraction and speed of the heart: used in the treatment of high blood pressure and angina pectoris
References in periodicals archive ?
Unfortunately, beta-blockers do not have an effect beyond blood pressure and heart rate lowering in patients with diastolic heart failure.
The use of beta-blockers and the importance of heart rate control in the perioperative and surgical intensive care settings.
Meta-analysis of carvedilol versus beta 1 selective beta-blockers (atenolol, bisoprolol, metoprolol, and nebivolol).
One of the most persuasive pieces of evidence of the shortcomings of beta-blockers as first-line agents for uncomplicated hypertension to appear since the release of the 2007 AhA scientific statement was a meta-analysis of six meta-analyses.
Effective heart rate control for the whole perioperative period was achieved in 29 (9%) patients on perioperative beta-blockers and 10 (3%) patients not on perioperative beta-blockers, P=0.
The finding that beta-blockers produce a different pattern of blood pressure lowering to thiazides when used as second-line drugs certainly deserves further attention as it might explain why beta-blockers appear to be less effective than thiazide diuretics at reducing adverse cardiovascular outcomes, particularly in older individuals.
Beta-blockers therapy and symptoms of depression, fatigue, and sexual dysfunction.
A total of 18% of patients were already on beta-blockers when they entered the hospital.
Around two million people take beta-blockers in the UK, although some take the drugs for conditions such as angina and anxiety and will be unaffected by the guidance.
Family doctors are to be advised not to prescribe beta-blockers as the routine "first-line" therapy for high blood pressure in favour of other treatments.
In these situations, the beta-blockers improve survival.