Beta-blockers are commonly used by musicians and public speakers to calm things down before performances. But they have a much more serious role in modern medicine. The adrenalin system is activated in all of us when we're frightened or otherwise under stress. This is a major source of cardiovascular risk. Almost all the cells of the body have receptors on their walls which respond to adrenalin released under stress. This increases our heart rate and blood pressure in preparation for 'fight or flight'.
These receptors have been classified into several types, and the beta-receptors are one important subtype. In 1958 the first drug which blocked the effects of adrenalin on the heart was synthesised and by 1962 the first clinically useful agent, propranolol, was developed. Propranolol revolutionised the medical management of angina pectoris, arrhythmias and blood pressure. This class of agents is one of the most important in use today.
In recent years, drugs that more selectively affect the heart, such as atenolol, metoprolol and carvedilol have been developed. As a general rule we cannot say that one beta-blocker is more effective in improving cardiovascular outcome than any of the others. Beta-blockers are generally well tolerated. Side-effects can include a slow heart rate, fatigue, a depressed mood, unusual dreams, and in susceptible individuals, asthma attacks. All these are more likely to occur in the elderly. Contraindications to B-blockers are extremely slow heart rate, pre-existing heart conduction block or a history of asthma.
The New Role
In the last decade, a new role of B-blockers has revolutionised the management of heart failure patients. In patients with reduced pump function and heart failure, whether from heart attack damage or from some other causes, B-blockers (specifically, bisoprolol, long acting metoprolol and carvedilol) prevent further deterioration, helping them live longer and feel better than ever before.
Targeting blood pressure for primary prevention
Beta-blockers are very effective BP meds-by blocking adrenaline, heart rate and blood pressure are both lowered, and heart attacks and fatalities are prevented. There is currently some debate as to whether they are as good as other classes of BP meds for preventing strokes, and therefore whether they should be the firstline agents when being used primarily for BP. So far, we cannot draw a firm conclusion about this.
Beta-blockers are very effective BP meds-by blocking adrenaline, heart rate and blood pressure are both lowered, and heart attacks and fatalities are prevented. There is currently some debate as to whether they are as good as other classes of BP meds for preventing strokes, and therefore whether they should be the firstline agents when being used primarily for BP. So far, we cannot draw a firm conclusion about this.
Major benefits in secondary prevention
The biggest role for these meds is in secondary prevention after a heart attack. The benefit seems to begin almost immediately, so intravenous metoprolol is commonly given in emergency rooms to heart attack victims. In patients with prior heart attacks, betablockers have reduced deaths anywhere from 19 to 48%, with a 28% decrease in second heart attacks as well.
Beta-blockers appear to protect people after a heart attack by preventing serious arrhythmia and sudden death, one of the major long-term risks for survivors. They are a critical line in the defence against future cardiac problems, and should be started immediately after an attack and continued at least for the first year, probably indefinitely.
We don't yet know if their protective effect wanes over very long time periods. Evidence also suggests they can be safely taken by diabetics. In patients with angina pectoris, the chest discomfort that comes with exertion in someone with blockages and stable angina (chest pain that occurs with stress or activity), beta-blockers make the heart work less hard, rebalance oxygen needs and reduce the symptoms of discomfort
Safe to Drink?
People say that drinking water stored in copper vessels is good for health. I think it's toxic! -Mani, Kolkata
We need a tiny amount of copper in our diet, it is what is called an essential trace element. Except for certain unusual disease situations, deficiency of the metal is extremely rare, as it is widely present in food-in wholegrain cereals, fruits and nuts. In fact, ingesting excess amounts of copper can be toxic, with symptoms ranging from vomiting blood to kidney damage.
Although high concentrations of copper can kill bacteria, this property has been used mainly for agricultural work, and even there, copper compounds are considered toxic, with many better alternatives. Some communities traditionally store drinking water in copper vessels, and even though several health benefits are attributed to the metal, it is difficult to say how much copper actually dissolves in the water. However, it would be quite reasonable to say that it could contribute to toxicity, without giving any benefits, as most people are ingesting enough of the metal anyway. Do remember that a few years ago, another commonly used metal, aluminium, was linked to Alzheimer's disease. There are more effective and less toxic ways to store clean water. ( preventionindia.in )
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