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 ?
In our study, worsening renal function did not appear to be caused by beta-blocker therapy and all patients were already on ACE inhibitors.
"Beta-blockers have been shown to improve survival, reduce hospitalizations and improve the strength and size of the heart in patients with systolic heart failure.
In experiments with a different mouse model of pancreatic cancer, the CUMC team demonstrated that treating mice with chemotherapy and nonselective beta-blockers, which are used to treat a variety of conditions, lived significantly longer than mice treated with chemotherapy alone.
APACHE-II scores and maximum HR<100/min were independent variables predicting ICU mortality in multivariate logistic regression analysis whereas usage of beta-blockers was not.
A 2013 stratified subset meta-analysis used data from landmark randomized controlled trials (RCTs) that evaluated beta-blockers vs placebo in patients with systolic heart failure to compare metoprolol succinate (MERIT-HF) vs placebo with bisoprolol (CIBIS-II), carvedilol (COPERNICUS), and nebivolol (SENIORS-SHF) vs placebo (table).
Other beta-blockers have a more general action and block shaking and sweating.
The MAPHY study demonstrated the significantly lower risk for coronary events in patients on metoprolol, a lipophilic beta-blocker, as compared to those on diuretics [31].
We calculated a priori that to observe a 50% increase in effective perioperative beta-blocker therapy in patients prescribed perioperative betablockers from 40% to >60% or a 50% decrease from 40% to <20%, we needed 260 patients in each cohort (type I error 0.05, type II error 0.20).
Using beta-blockers as a second-line therapy in combination with certain anti-hypertensive drugs significantly lowers blood pressure in patients with hypertension, according to a systematic review by Cochrane Researchers.
* contraindications for beta-blocker use (other than history of depression)
A Beta-blockers are used to treat high blood pressure, heart failure and other conditions.