| 单词 | beta-blocker |
| 释义 | beta-blockerbe·ta-block·erB0213000 (bā′tə-blŏk′ər, bē′-)beta-blockerbeta-blockerbeta-blockerorbeta-adrenergic blocking agent(bā`tə ăd'rənûr`jĭk), drug that reduces the symptoms connected with hypertensionhypertensionor 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). ..... Click the link for more information. , 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. ..... Click the link for more information. , 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. ..... Click the link for more information. , 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. ..... Click the link for more information. 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. ..... Click the link for more information. . 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. ..... Click the link for more information. 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). ..... Click the link for more information. , 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-blockerSee beta-blocker beta-blockerbeta[ba´tah]Because of their effects on the heart, these agents are used to treat angina pectoris, hypertension, and cardiac arrhythmias. And, because they decrease the workload of the heart, they are effective in reducing the long-term risk of mortality and reinfarction after recovery from the acute phase of a myocardial infarction. They are an important adjunct in treatment of heart failure and are also used for prophylaxis of migraine. Nonselective beta-adrenergic blocking agents affect both types of receptors and can produce bronchospasm in patients with asthma or chronic obstructive pulmonary disease. If such patients need one of these drugs, they should be given a cardioselective one that preferentially blocks the β1-receptors in the heart. Nonselective agents include propranolol" >propranolol (Inderal), used for treatment of angina, hypertension, arrhythmias, and migraine and for prophylaxis after the acute phase of a myocardial infarction; nadolol" >nadolol (Corgard), used for treatment of angina and hypertension; and timolol" >timolol, used as an ophthalmic preparation (Timoptic) for treatment of glaucoma and as an oral preparation (Blocadren) for treatment of hypertension and for prophylaxis after the acute phase of a myocardial infarction. Cardioselective beta-adrenergic blocking agents are used for treatment of hypertension and include atenolol" >atenolol (Tenormin) and metoprolol" >metoprolol (Lopressor). blocker[blok´er]β-ad·re·ner·gic block·ing a·gentbeta-blocker(bā′tə-blŏk′ər, bē′-)beta-blockerAny of a class of agents that blocks 1 and/or 2 adrenergic receptors in the nervous system, modulating cardiac functions, respiratory functions and the dilation of blood vessels.Effect Slowed heart rate, lowered blood pressure, reduced anxiety. Indications • General medicine Angina, arrhythmias, hypertension, mitral valve prolapse, tachycardia, migraine, etc. • Psychiatry Aggression and violence, anxiety-related tremors and lithium-induced tremors, neuroleptic-induced akathisia, social phobias, panic states and alcohol withdrawal. Examples Carvedilol, sotalol, metoprolol, propranolol, atenolol, esmolol. Beta-blockerbeta-blocker |
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