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. (October 2017)
Large differences exist in the pharmacology of agents within the class, thus not all beta blockers are used for all indications listed below.
Indications for beta blockers include:
Beta blockers have also been used for:
Congestive heart failure
Although beta blockers were once contraindicated in congestive heart failure, as they have the potential to worsen the condition due to their effect of decreasing cardiac contractility, studies in the late 1990s showed their efficacy at reducing morbidity and mortality.
Bisoprolol, carvedilol, and sustained-release metoprolol are specifically indicated as adjuncts to standard ACE inhibitor and diuretic therapy in congestive heart failure, although at doses typically much lower than those indicated for other conditions. Beta blockers are only indicated in cases of compensated, stable congestive heart failure; in cases of acute decompensated heart failure, beta blockers will cause a further decrease in ejection fraction, worsening the patient's current symptoms.
Beta blockers are known primarily for their reductive effect on heart rate, although this is not the only mechanism of action of importance in congestive heart failure.renin–angiotensin system at the kidneys. Beta blockers cause a decrease in renin secretion, which in turn reduces the heart oxygen demand by lowering extracellular volume and increasing the oxygen-carrying capacity of blood. Heart failure characteristically involves increased catecholamine activity on the heart, which is responsible for a number of deleterious effects, including increased oxygen demand, propagation of inflammatory mediators, and abnormal cardiac tissue remodeling, all of which decrease the efficiency of cardiac contraction and contribute to the low ejection fraction. Beta blockers counter this inappropriately high sympathetic activity, eventually leading to an improved ejection fraction, despite an initial reduction in ejection fraction.
Beta blockers, in addition to their sympatholytic β1 activity in the heart, influence the
Trials have shown beta blockers reduce the absolute risk of death by 4.5% over a 13-month period. In addition to reducing the risk of mortality, the numbers of hospital visits and hospitalizations were also reduced in the trials.
Officially, beta blockers are not approved for anxiolytic use by the U.S. Food and Drug Administration. However, many controlled trials in the past 25 years indicate beta blockers are effective in anxiety disorders, though the mechanism of action is not known. The physiological symptoms of the fight-or-flight response (pounding heart, cold/clammy hands, increased respiration, sweating, etc.) are significantly reduced, thus enabling anxious individuals to concentrate on the task at hand.
Musicians, public speakers, actors, and professional dancers have been known to use beta blockers to avoid performance anxiety, stage fright, and tremor during both auditions and public performances. The application to stage fright was first recognized in The Lancet in 1976, and by 1987, a survey conducted by the International Conference of Symphony Orchestra Musicians, representing the 51 largest orchestras in the United States, revealed 27% of its musicians had used beta blockers and 70% obtained them from friends, not physicians. Beta blockers are inexpensive, said to be relatively safe, and on one hand, seem to improve musicians' performances on a technical level, while some, such as Barry Green, the author of "The Inner Game of Music" and Don Greene, a former Olympic diving coach who teaches Juilliard students to overcome their stage fright naturally, say the performances may be perceived as "soulless and inauthentic".
The use of beta blockers around the time of cardiac surgery decreases the risk of heart dysrhythmias. Starting them around the time of other types of surgery, however, may worsen outcomes.