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 in the following conditions:
- Hypertrophic obstructive cardiomyopathy
- Acute dissecting aortic aneurysm
- Marfan syndrome (treatment with propranolol slows progression of aortic dilation and its complications)
- Prevention of variceal bleeding in portal hypertension
- Possible mitigation of hyperhidrosis
- Social anxiety disorder and other anxiety disorders
Congestive heart failure
Although beta blockers were once contraindicated in congestive heart failure, as they have the potential to worsen the condition, studies in the late 1990s showed their positive effects on morbidity and mortality in congestive heart failure.
Bisoprolol, carvedilol and sustained-release metoprolol are specifically indicated as adjuncts to standard ACE inhibitor and diuretic therapy in congestive heart failure.
Beta blockers are primarily known for their reductive effect on heart rate, although this is not the only mechanism of action of importance in congestive heart failure.
Beta blockers, in addition to their sympatholytic B1 activity in the heart, influence the renin/angiotensin system at the kidneys.
Beta blockers cause a decrease in renin secretion, which in turn reduce the heart oxygen demand by lowering extracellular volume and increasing the oxygen carrying capacity of blood.
Beta blockers sympatholytic activity reduce heart rate, thereby increasing the ejection fraction of the heart despite an initial reduction in ejection fraction.
Trials have shown that beta blockers reduce the absolute risk of death by 4.5% over a 13 month period. As well as reducing the risk of mortality, the number of hospital visits and hospitalizations were also reduced in the trials.
Anxiety and performance enhancement
Some people have used beta blockers for performance enhancement, and especially to combat 'performance anxiety'. In particular, musicians, public speakers, actors, (especially, pornographic actors), and professional dancers, have been known to use beta blockers to avoid stage fright and tremor during public performance and especially auditions.
The physiological symptoms of the fight/flight response associated with performance anxiety and panic (pounding heart, cold/clammy hands, increased respiration, sweating, etc.) are significantly reduced, thus enabling anxious individuals to concentrate on the task at hand.
Stutterers also use beta blockers to avoid fight/flight responses, hence reducing the tendency to stutter.
Officially, beta blockers are not approved for anxiolytic use by the U.S. Food and Drug Administration.
Since they lower heart rate and reduce tremor, beta blockers have been used by some Olympic marksmen to enhance performance, though beta blockers are banned by the International Olympic Committee (IOC).
Although they have no recognisable benefit to most sports, it is acknowledged that they are beneficial to sports such as archery and shooting.
A recent, high-profile transgression took place in the 2008 Summer Olympics, where 50 metre pistol silver medallist and 10 metre air pistol bronze medallist Kim Jong-su tested positive for propranolol and was stripped of his medal.
Preventing PTSD
Post Traumatic Stress Disorder is theorized to be the result of neurological patterns caused by adrenaline and fear in the brain. By administering beta blockers immediately following a traumatic event, as well as over the next couple weeks, the formation of PTSD has been reduced in clinical studies.
Further Reading
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