Beta blockers, in addition to their sympatholytic β1 activity in the heart, influence the renin–angiotensin system at the kidneys. Beta blockers cause a decrease in renin secretion, which in turn reduces the heart oxygen demand by lowering the extracellular volume and increasing the oxygen-carrying capacity of the blood. Heart failure characteristically involves increased catecholamine activity on the heart, which is responsible for several 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. 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.Therapeutic administration of beta blockers for congestive heart failure ought to begin at very low doses (1/8 of target) with a gradual escalation of the dose. The heart of the patient must adjust to decreasing stimulation by catecholamines and find a new equilibrium at a lower adrenergic drive. Anxiety
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 implications is that further research could affect conclusions reached. Several hearing conservation programs have been developed to educate a variety of audiences about the dangers of NIHL and how to prevent it. Dangerous Decibels aims to significantly reduce the prevalence of noise induced hearing loss and tinnitus through exhibits, education and research. Were hEAR for You is a small non-profit that distributes information and ear plugs at concert and music festival venues. The Buy Quiet program was created to combat occupational noise exposures by promoting the purchase of quieter tools and equipment and encourage manufacturers to design quieter equipment. The National Institute on Deafness and Other Communication Disorders developed the Its a Noisy Planet. Protect their Hearing educational campaign to inform preteens, parents, and educators about the causes and prevention of NIHL. The National Institute for Occupational Safety and Health partnered with the National Hearing Conservation Association in 2007 to establish the Safe-in-Sound Excellence and Innovation in Hearing Loss Prevention Awards to recognize organizations that are successfully implementing hearing loss prevention concepts into their daily routines. Medication
Medications are still being researched to determine if they can prevent NIHL. No medication has been proven to prevent or repair NIHL in humans. There is evidence that hearing loss can be minimized by taking high doses of magnesium for a few days, starting as soon as possible after exposure to the loud noise. A magnesium-high diet also seems to be helpful as an NIHL-preventative if taken in advance of exposure to loud noises.