What Are Beta-Blockers? What Are Beta-Blockers For?

Beta-blockers, also known as beta-adrenergic blocking agents, beta-adrenergic antagonists, or beta antagonists, are a type of drug that block the action of the sympathetic nervous system of the heart, resulting in a relief of stress on the heart.

A beta-blocker blocks beta-adrenergic substances, for example adrenaline (apinephrine) in the involuntary nervous system (autononomic nervous system). Beta-blockers slow down the heart beat, reduce the force of the heart muscle's contractions, and decrease blood vessel contraction in the heart, brain, and the rest of the body.

Patients with cardiac arrhythmias (abnormal heart rhythms), tachycardias (accelerated heart rates), or irregular heart rhythms (atrial fibrillation), such as premature ventricular beats may be prescribed beta-blockers. They may also be useful in treating angina because they lower the heart muscle's demand for oxygen - angina pectoris occurs when the heart's demand for oxygen is greater than the supply.

Beta-blockers are useful in the treatment of high blood pressure (hypertension) because their effects on blood vessels lowers blood pressure. They are also key drugs in improving survival rates for patients after a heart attack.

Beta-blockers are also used for preventing migraine headaches and some familial or hereditary tremors.

In other words, beta-blockers are known as beta- adrenoreceptor blocking agents and are used to treat:

Commonly

• Angina
• Heart failure
• High blood pressure (hypertension)
• irregular heart beat (atrial fibrillation)
• Myocardial infarction (heart attack)
  
  Less commonly
• Prevention of migraine
• Thyrotoxicosis (overactive thyroid)
• Anxiety
• Tremor
• Glaucoma (as eye drops)

The first clinically useful beta adrenergic receptor antagonist was called Propranolol. It was invented by Sir James W. Black (born 1924), a Scottish doctor and pharmacologist. Sir James also synthesized Cimetidine (for the treatment of heartburn and peptic ulcers) and was awarded the Nobel Prize for Medicine in 1988. Propranolol revolutionized the medical management of angina pectoris - it is considered as one of the major contributions to clinical medicine and pharmacology of the 20th century.

According to Medilexicon's medical dictionary

A beta-adrenergic blocking agent is "a class of drugs that competes with β-adrenergic agonists for available receptor sites; some compete for both Beta₁ and Beta₂ receptors (propranolol) whereas others are primarily either Beta₁ (metoprolol) or Beta₂ blockers; used in the treatment of a variety of cardiovascular diseases for which beta-adrenergic blockade is desirable."

Types of beta-blockers

There are various types of beta-blockers (beta-adrenoceptor blocking agents). Which one a patient has depends on his/her condition.

Below are some examples:

Acebutolol (Sectral)
Atenolol (Tenormin)
Betaxolol (Betoptic)
Bisoprolol (Cardicor, Emcor, Zebeta)
Carteolol (Teoptic)
Carvedilol (Coreg, Eucardic)
Celiprolol (Celectol)
Labetalol (Trandate)
Levobunolol (Betagan)
Metipranolol (Metipranolol Minims)
Metoprolol (Betaloc, Lopresor, Lopressor, Toprol XL)
Nadolol (Corgard)
Nebivolol (Bystolic, Nebilet)
Oxprenolol (Trasicor)
Pindolol (Visken)
Propranolol (Inderal LA)
Sotalol (Beta-Cardone, Sotacor)
Timolol (Betim, Nyogel, Timoptol)

What do beta-blockers do?

Beta-blockers block the release of noradrenalin in parts of the body. Noradrenalin is released by the nerves when they are stimulated - it is a chemical that conveys messages to other parts of the body, including muscles, blood vessels and the heart.

• Heart problems - for a patient with heart problems beta-blockers can reduce the workload for the heart; so that it does not have to work so hard to supply all parts of the body with oxygen-rich blood. For people with angina, heart failure, or after a heart attack, reducing the heart's workload is crucial.
  
  Beta-blockers can also block the stimulation of the heart form electrical impulses - they can control irregular heartbeats - thus lowering the activity of the heart and slowing down the heart rate.


• Hypertension - beta-blockers lower blood pressure by slowing down the heart rate, as well as reducing the force of the heart. Blood still gets to all parts of the body, but at reduced pressure.


• Glaucoma - pressure within the eyeball is reduced with beta-blocker eye drops. The medication lowers the production of fluid inside the eye ball (aqueous humor).

Things to bear in mind with beta-blockers

The following people should not take beta-blockers:

• Patients with a history of asthma (unless the doctor says so)
• Patients with a history of bronchospasm (unless the doctor says so)
• Patients with second or third degree heart block
• Patients with severe peripheral arterial disease (including Raynaud's syndrome)
• Patients with worsening, unstable heart failure (can be used for stable heart failure)

For the following people, beta-blockers should be used with caution:

• Patients with diabetes, especially those with regular episodes of low blood sugar (hypoglycemia)
• Patients with MG (myasthenia gravis)
• Patients with a slow heart rate (bradycardia)
• Patients with low blood pressure (hypotension)
• Patients with hypertension that results from an adrenal gland tumor (pheochromocytoma)
• Patients with high blood acid levels (metabolic acidosis)
• Patients with Prinzmetal angina

Pregnancy and breastfeeding - in some cases certain types of beta-blockers may be used.

Getting off beta-blockers - Patients must not stop taking beta-blockers suddenly without their doctor's advice and close supervision. Suddenly ceasing beta-blocker treatment may exacerbate the patient's condition, especially after a heart attack or for the treatment of angina.

What are the side effects of beta-blockers?

The most common side effects are:

• Cold feet
• Cold hands
• Diarrhea
• Fatigue
• Nausea
• Very slow heartbeat

The following less common side effects are also possible:

• Sleeping difficulties and disturbances
• Bad dreams (nightmares)
• Erectile dysfunction (male inability to achieve or sustain an erection during sex)

Driving - some patients may experience dizziness or fatigue; in such cases they should not drive. However, this is rare.

Beta-blocker interactions with other drugs

Drug interaction is the extra effects two different medicines can have on the body when taken together - effects beyond their primary purposes. Beta-blockers can interact with the following medications:

• Antipsychotics - these medications are commonly prescribed for patients with bipolar disorder or schizophrenia. When taken with some beta-blockers the risk of arrhythmias is greater.


• Clonidine - a medication prescribed for either patients with hypertension (high blood pressure) or migraines. A patient who is taking both clonidine and beta-blockers and then suddenly stops taking clonidine has a greater risk of experiencing a sudden and sharp rise in blood pressure (rebound hypertension).


• Digoxin - prescribed for patients with congestive heart failure and certain cardiac arrhythmias. When taken with beta-blockers there is a higher risk of slow heart rate (bradycardia).


• Diltiazem - a medication that dilates blood vessels, prescribed for patients with angina pectoris or hypertension. When taken with beta-blockers there is a higher risk of slow heart rate (bradycardia).


• Drugs to control high blood pressure (antihypertensives) - when taken with beta-blockers the patient may experience hypotension (a serious drop in blood pressure).


• Drugs to control irregular heartbeats (anti-arrhythmics) - when taken with beta-blockers the risk of impaired function of the heart (myocardial depression) is greater, as is the risk of irregular heartbeats (arrhythmias).


• Mefloquine - a drug for the treatment of malaria resistant to chloroquine phosphate. When taken with beta-blockers the result may be bradycardia.


• Nifedipine - this drug reduces calcium ions available to heart and smooth muscle, used in the treatment of angina pectoris. When taken with beta-blockers there is a higher risk of hypotension (low blood pressure).


• Nisoldipine - a calcium channel blocker used in the treatment of high blood pressure (hypertension). When taken with beta-blockers there is a higher risk of hypotension (low blood pressure).


• Verapamil - used in the treatment of hypertension, angina pectoris, and certain cardiac arrhythmias. When taken with beta-blockers there is a higher risk of hypotension (low blood pressure).

Check with your pharmacist or doctor for a more comprehensive and up-to-date list of beta-blocker interactions.


P.S. Boost your Heart Health by eating Vitamin C and Vitamin D rich foods and fruits.



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Sulfonylureas for Diabetes increase risk of Heart Disease and Death, Study finds

Sulfonylureas, the first family of oral drugs used for treating type 2 diabetes, increase the risk of death from all causes by as much as 61% compared with the newer drug metformin, British researchers have found. Some researchers have suspected that the drugs carry an increased risk, but the new study reported online in BMJ.com is the first to quantify the risks. BMJ.com is the website of BMJ, formerly the British Medical Journal.

The good news from the study is that the new family of drugs called thiazolidinediones is not associated with an increased risk and that one of them, pioglitazone, actually reduces risk by as much as 39% compared with metformin.

Type 2 diabetes has reached epidemic status, with more than 180 million victims worldwide and nearly 24 million in the United States. It is most common among the elderly and is associated with obesity, but the growing incidence of obesity in youth is causing the disease to appear in an ever-younger population. Diabetes by itself doubles the risk of heart disease, which complicates the task of identifying increased risks from drugs. U.S. guidelines call for using metformin as first-line therapy for type 2 diabetes, and the new results support that recommendation.

The sulfonyureas, which include Glucotrol, Diabeta, Glipizide, Gliclazide, glyburide, Amaryl, chlorpropamide, tolbutamide and tolazamide, have been marketed in the United States since 1955 and are taken once or twice daily before meals. They stimulate the release of insulin by the pancreas and may help sensitize cells to the action of the hormone.

Dr. Paul Elliott, an epidemiologist at Imperial College London, and his colleagues studied health records of 91,521 diabetic men and women (with an average age of 65) in the U.K. General Practice Database between 1990 and 2005. Among that group, in an average follow-up period of seven years, there were 3,588 myocardial infarctions (heart attacks), 6,900 cases of congestive heart failure and 18,548 deaths.

Compared with metformin, the team observed a 24% to 61% excess risk for deaths from all causes among users of first- and second-generation sulfonylureas and an 18% to 30% excess risk of congestive heart failure for users of the second-generation drugs. The thiazolidinediones rosiglitazone (Avandia) and pioglitazone (Actos) were not associated with an increased risk of heart attacks. Actos was associated with a 31% to 39% decrease in risk of all-cause mortality compared with metformin. Comparing the two thiazolidinediones to each other, the team found that Avandia was linked to a 34% to 41% higher risk of death, but the team concluded the increased risk was not statistically significant when other factors were taken into account.

Experts cautioned, however, that the study suffers from a problem characteristic of all such retrospective studies -- researchers cannot know what diagnosis prompted physicians to describe specific drugs. High-risk patients with high blood levels of creatine, for example, are not likely to be prescribed metformin and would probably receive a sulfonylurea instead. Because the high creatine levels increase the risk of death by themselves, an increased risk might inappropriately be blamed on the drugs.


P.S. Protect your Heart by eating Vitamin C and Vitamin D rich foods and fruits.



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Body clock link to heart disease

Scientists have raised the possibility that cardiovascular disease is linked to disturbances in the body's 24-hour clock.

Working on mice, the Japanese team found a genetic risk factor for a form of high blood pressure is influenced by 24-hour or circadian rhythms.

The study appears online in the journal Nature Medicine.

Malfunctions in the body clock - which influences much of the body's chemistry - have been linked to many diseases.

And lead researcher Professor Hitoshi Okamura said the latest study was in line with data which suggested shift workers, long-distance flight crews and people with sleep disorders have a heightened risk of heart problems.

High blood pressure - known as hypertension - can lead to heart attack, stroke, kidney damage, and many other medical problems.

Many genes have been identified as being essential elements making up the circadian clock.

For example, mice lacking a pair of molecules known as cryptochromes have an abnormal circadian rhythm.

The latest study, by Kyoto University, found these mice were vulnerable to high blood pressure because of abnormally high levels of a hormone called aldosterone that prompts water retention in the kidneys.


Strong correlation

The researchers showed that the circadian clock directly controls a gene that plays a key role in production of the hormone.

The researchers say a similar gene is found in humans.

They stress more work is needed to determine whether a misfiring circadian clock can lead to high blood pressure in humans.

But Professor Okamura said the research raised the prospect of new ways to treat hypertension.

Professor Bryan Williams, an expert in hypertension at the University of Leicester, described the study as "fascinating".

He said: "We know that there is a strong correlation between time of day and cardiovascular events, which often coincide with the early morning surge in blood pressure.

"So this does provide some insights into the mechanism that might underpin blood pressure deregulation in some people."

Professor Williams said some people with high blood pressure were known to have high levels of aldosterone.

But he added: "What we don't know is how common this mutation might be in human hypertension."

Professor Jeremy Pearson, associate medical director at the British Heart Foundation, said: "Hypertension is common, but the genes controlling blood pressure are not well understood.

"Their identification will help design better treatments for high blood pressure."

But he also stressed more research was needed before it became clear whether the study had identified a potential target for new treatments.


P.S. protect your HEART by eating Vitamin C and Vitamin D rich foods and fruits.



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Cholesterol Plays Role in Heart Failure Risk

Abnormal cholesterol levels can significantly increase the risk of heart failure, a new study has found.

U.S. researchers analyzed data on 6,860 participants in the National Heart, Lung, and Blood Institute's Framingham Heart Study. None of the participants, average age 44, had coronary heart disease at the start of the study. After about 26 years of follow-up, 680 people had developed heart failure.


The incidence of heart failure was:

* 12.8 percent in participants with low levels of high-density lipoprotein (HDL, or "good") cholesterol. Low HDL is less than 40 milligrams per deciliter (mg/dL) in men and less than 50 mg/dL in women.

* 6.1 percent among participants with desirable HDL levels (at least 55 mg/dL in men and 65 mg/dL in women).

* 13.8 percent in participants with high levels (at least 190 mg/dL) of non-HDL cholesterol, which includes triglycerides and low-density lipoprotein (LDL, or "bad") cholesterol.

* 7.9 percent in those with desirable levels (less than 160 mg/dL) of non-HDL cholesterol.

When the researchers factored in age, sex, body mass index, blood pressure, diabetes and smoking, the risk of heart failure was 29 percent higher in participants with high non-HDL cholesterol than in those with lower levels, and 40 percent lower in those with high HDL-cholesterol than in those with lower levels.

Further analysis showed that the risk of heart attack was 13 percent higher in participants with high non-HDL cholesterol and 25 percent lower in those with high HDL cholesterol.

"This study goes a step further in implicating cholesterol levels (both HDL and non-HDL) in heart failure and suggests that cholesterol-altering therapy may have long-term benefits in preventing heart failure above and beyond its effects on preventing [heart attack]," study senior author Dr. Daniel Levy, director of the Framingham Heart Study, said in a news release from the American Heart Association.


P.S. maintain good cholesterol by eating Vitamin C and Vitamin D rich foods and fruits.



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Birth Control Pills May Cause a Heart Attack or Stroke

Yaz, Yasmin and Ocella are popular birth control pills that have been linked to alarming side-effects such as heart attacks and strokes. Reportedly, Drospirenone, the key ingredient in Yaz, Yasmin and Ocella is responsible for raising the risk of heart attack and stroke. It is important to note that according to some reports, no other birth control pill contains Drospirenone.

Yaz, Yasmin and Ocella can cause strokes and heart attacks by creating abnormal blood clots. Ordinarily, blood clots serve the important function of stopping bleeding from cuts. Within the body, the blood clotting process repairs damage to the skin, blood vessels and other body tissues. It has been reported however, that the use of Yaz, Yasmin and Ocella can result in unnecessary blood clotting within a blood vessel, vein or artery. If the blood clot causes a blockage near the heart, the clot can prevent blood flow from reaching the heart, resulting in a heart attack. If the blood clot creates a blockage in the brain, the blockage can cause a stroke. It has been suggested that the combination of chemicals and hormones in Yaz, Yasmin and Ocella can increase the risk of blood clots by more than 600%.

A leading personal injury law firm, Weitz & Luxenberg is offering free, online case reviews to those who have suffered side-effects from using Yaz, Yasmin or Ocella. For a free case review, send an e-mail to kumarsingh011@gmail.com. In your e-mail, please state the following:

# Your name
# Your date of birth
# The start date and end date of your use of Yaz, Yasmin or Ocella
# A description of the side-effects that you experienced


About Weitz & Luxenberg lawyers


Weitz & Luxenberg is a leading personal injury law firm. The firm has won more than $1 billion in a wide range of personal injury cases. The cases that the firm handles include defective products such as Yaz birth control pills and asbestos cancer cases such as mesothelioma. Weitz & Luxenberg has successfully represented shipyard workers, boilermakers and others who have been diagnosed with mesothelioma from job-related asbestos exposure.

Weitz & Luxenberg has been recognized as the "Best Lawyers of New York" by New York Magazine.

Remember: The law limits your time to file a lawsuit. Don't lose your rights by waiting too long to explore your legal options.



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Vitamin D Deficiency Increases the Risk of Heart Disease Among Diabetics

New research suggests that people with diabetes may face an increased risk of heart disease if they have a deficiency of vitamin D. An article in Science News magazine cites a study at Washington University School of Medicine in St. Louis indicating that macrophages, the immune cells that normally fight heart disease by absorbing LDL cholesterol, may do their job too well in cases of vitamin D deficiency. Instead of helping to prevent heart disease in these patients, the macrophages may actually contribute to it.

Endocrinologist Carlos Bernal-Mizrachi and his colleagues tested blood samples from 76 obese people, average age 55, who had type 2 diabetes, high blood pressure and low vitamin D levels. From these samples, the researchers cultured macrophages and exposed the immune cells to LDL cholesterol (the bad kind). They found that macrophages from type 2 diabetes patients showed a greater tendancy to absorb excessive amounts of LDL when they were cultured without vitamin D than when they were bathed in the vitamin. This transformed the macrophages into cholesterol-filled foam cells, the building blocks of arterial plaque.

Previous research has suggested that vitamin D deficiency may contribute to the risk of heart disease, but this is the first indication of the cellular mechanism that actually causes the increased risk.

Foam cells are part of the debris that collects inside blood vessels, eventually forming a fibrous cap of plaque. When the plaque ruptures and a blood clot forms, a stroke or heart attack can occur.

The study found that non-diabetics showed much less of this effect than diabetic patients did.

Further research by the same group of scientists has shed light on the reason for these results. In diabetic people, vitamin D helps reduce stress to the endoplasmic reticulum, which controls many cell functions. Reducing stress causes the macrophages to absorb less LDL cholesterol. In cases of vitamin D deficiency, this stress reduction does not take place, and the macrophages absorb more LDL cholesterol than they should. The stress also contributes to inflammation, which releases proteins that degrade plaque and lead to cap breakdown.

Though the results are preliminary and more research will be done on this question in the future, it appears that people with diabetes should pay attention to their vitamin D levels.

Writing in the health section of the Today Show website, nutrition and health editor Joy Bauer gives some good, basic information about the vitamin and how to make sure you’re getting enough of it.

There are three ways of getting vitamin D: exposure to sunlight, eating vitamin D-rich foods, and taking supplements.

Regular exposure to sunlight allows your body to make its own vitamin D. All you need is about 15 minutes of direct sun, a few times a week. However, you should use common sense and limit your exposure to prevent sunburn.

In addition to sunlight, you can also get vitamin D from certain foods. These include fish such as mackerel, salmon, and sardines, as well as shrimp. Skim milk and fortified yogurts are good, too, as are fortified cereals. Shiitake mushrooms are also very high in vitamin D.

However, since food sources are limited, it might be a good idea to consider a supplement. If you take one, be sure that it contains at least the Daily Value, which is 400 IU. Women taking extra calcium should get a brand that also includes vitamin D, preferably D3 (cholcaciferol, the most potent form.)

An article at DermNet NZ, a health Web site set up by the New Zealand Dermatological Society, stresses that sunlight is the best way to get vitamin D without risking overdose. Your body will not make more of the vitamin than it needs, so there is a natural safeguard against getting too much of it that way. If you are taking a supplement, it is possible to get an overdose of the vitamin, which can cause nausea, vomiting, poor appetite, constipation, weakness and weight loss. An overdose of vitamin D can also raise your blood calcium level, sometimes causing confusion and heart rhythm abnormalities. It should be stressed that people taking vitamin D supplements should never exceed the recommended dosage.

The information in this article is not intended as a substitute for a doctor’s advice. Always consult your doctor when considering dietary changes, supplements, etc.

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