Beta-Blockers: Facts, Functions, When is it Advised, Types, Side Effects, Cautions

What are Beta Blockers?

Beta-blockers are a category of drugs mainly used to control abnormal heart rhythms and to safeguard the heart from a second heart attack after the first has already taken place. They are also extensively used to cure hypertension or high blood pressure. This article discusses the role, indications, and contraindications of beta-blockers.

Beta-blockers are present in the cells of the heart muscles, smooth muscles, airways, arteries and kidneys and other tissues of the sympathetic nervous system. These medications provide a hindrance to the binding of the adrenaline receptor cells and stress hormones. They also debilitate the results of the stress hormones.

Facts About Beta Blockers

Beta-blockers are advised by medical practitioners to patients whose heart rate needs to be slowed down. These drugs are frequently suggested in cases of abnormal heart rates, angina, and high blood pressure. These drugs have also been found effective in relieving pain from glaucoma, overactive thyroid, and anxiety.

Functions of Beta Blockers

Beta-blockers work by obstructing the adrenaline and noradrenaline hormones in the sympathetic nervous system. The sympathetic nervous system is a part of the autonomic nervous system, which activates the fight or flight response.

An overdose of these drugs can cause an increase in heartbeat, excessive sweating, high blood pressure, anxiety, and palpitation. These drugs reduce the release of stress hormones, which in turn decreases the rapid oxygen supply and also reduces the stress on the heart. These drugs reduce the power of connections in the heart muscles and blood vessels in the heart, the brain and all other parts of the body. They also block the production of angiotensin which is a hormone produced by the kidneys. The reduction of this hormone lightens and broadens the blood vessels which in turn smoothens the blood flow throughout the vessels.

When are Beta Blockers Advised?

Beta-blockers are indicated and are approved for use by the FDA for treatment of tachycardia, hypertension, myocardial infarction, coronary artery disease, and hyperthyroidism.1

Beta-blockers are advised by the doctors to treat the following heart conditions in patients all around the world:

Angina – This ailment is also known as ischemic chest pain. This type of pain occurs in the chest as a cause of the reduction of the supply of blood to the heart. Beta-blockers help in this condition by obstructing the demand for oxygen in the heart and by reducing the risk of angina attacks. Doctors prescribe beta-blockers as the primary type of treatment in patients with this condition. These drugs can either be used alone or can be used in combination with calcium channel blockers.

Beta-Blockers in Case of Heart Failure – Beta-blockers are found to be effective in treating people with heart failure caused by impaired contraction of the left ventricle. These drugs also increase the life expectancy rate. Doctors recommend their patients to use these drugs no matter how severe their heart condition is. These drugs are advised to be used with an angiotensin-converting enzyme to reap maximum benefits.

Heart Rhythm Disorders and Beta Blockers – These drugs are used to check the abnormal heart rhythm in patients with Atrial Fibrillation (AF). These drugs slow down the heart rate by reducing the symptoms caused by AF. They are also effective in improving fatigue and application.

Recurrent Heart Attacks – Beta-blockers are also found helpful in protecting the heart from further risk of heart attacks. If a patient has suffered from a heart attack earlier, then these drugs are prescribed by their doctor to keep the further ones in check. This treatment is usually long term and continues for their entire life.

Blood Pressure – Beta-blockers are prescribed to patients with high blood pressure to reduce blood pressure. These drugs are used in combination with angiotensin-converting calcium channel blockers.

Glaucoma and Beta Blockers – This is an eye condition, which can cause blindness. Beta-blockers are used in the form of eye drops, which reduce the increased pressure in the eyeballs. It also reduces the formation of fluids in the eyeballs.

Beta-Blockers in the Case of Anxiety – This is an emotional condition characterized by worry and fear, which are strong enough to disturb a person’s daily activities. Beta-blockers are used to control the physical consequences of anxiety such as excessive sweating, trembling, and palpitations. The mental health, however, needs to be treated through counseling and other appropriate therapies, as advised medically.

Overactive Thyroid and Usage of Beta-Blockers – Hyperthyroidism is the overproduction of hormones by the butterfly-shaped glands in the neck. This condition is treated by beta-blockers by reducing the heart rate and tremors.

Types of Beta Blockers

There are mainly three variants of beta-blockers. They can be classified into three broad categories. Namely:

Nonselective Beta-Blockers:

These are one of the ancient types and are to be used with precautions. People with asthma and other lung conditions should stay away from it. If it is found necessary to use, then these drugs should be used under medical supervision.

Cardio Selective Beta-Blockers:

These beta-blockers are used to block beta type 1 receptors and do not affect beta type 2 receptors. Hence, these drugs are safe for people with lung disorders. Studies show that these types of beta-blockers are prescribed for people with diabetes and chronic obstructive pulmonary disease (COPD).2

Third Generation Beta-Blockers:

These types of beta-blockers are found to be the most effective and are proven to be the best. These drugs not only block beta receptors but also obstruct alpha receptors. They relax the blood vessels and further trigger the inner lining of the blood.

Examples of Beta Blockers

Some beta-blockers directly treat heart conditions while others affect both heart and blood vessels. The selection of these drugs is based on the ailments that are being treated.

Some examples of beta-blockers are as follows:

  • Acebutolol
  • Atenolol
  • Bisoprolol
  • Metoprolol
  • Nadolol
  • Nebivolol
  • Propranolol.

Side Effects of Beta Blockers

Beta-blockers are usually well treated without any significant side effects but still, some of the possible side effects of beta-blockers, noted in some patients include the following,

There are some other uncommon side effects as well. They are:

Cautions for Beta Blockers

People with these conditions are advised to take this drug in consultation with their doctors:

Diabetic people or people with low blood sugar should keep a track of their blood sugar level regularly because this drug can interfere with the sugar levels.

Beta Blockers are not used by patients with asthma because these medications may initiate or activate severe incurable asthma attacks. For people with diabetes, these drugs can obstruct the signs of low blood sugar by reducing rapid heartbeat. Beta-Blockers can interfere with the cholesterol levels by slightly increasing the triglyceride levels and it also might slightly decrease the good cholesterol levels.

Reactions of Beta Blockers

Beta-blockers can react with the following drugs:

  • Anti-hypertensive
  • Anti-anginal drugs
  • Anti-arrhythmic
  • Anti-steroidal medications
  • Anti-ulcer medications
  • Anesthetics
  • Warfarin.

How to Use Beta Blockers?

Beta-blockers should be used solely and only as directed by the physician. No individual should experiment with this drug or take this drug without consulting their doctor. Doctors often prescribe the dosage of this drug as 1-2 times a day. This drug should not be started or stopped without consulting a doctor. If a dose is missed it should be taken right away but if it has been more than 4-6 hours the missed dose should not be taken. An overdose of this drug can be fatal.

When to Consult a Doctor: Warning Signs After Taking Beta Blockers

Beta-blockers should only be used as prescribed by the doctor. However, if any of these problems are faced, a doctor should be consulted immediately:

  • If a patient feels dizzy for more than several days.
  • If a patient finds it difficult to breathe.
  • If a patient is having chest pain.
  • If a patient retains severe body fluid.
  • If swelling of hands, legs, and feet are found to be severe.
  • If a person becomes obese for no specific reason.

Questions To Keep In Mind While Taking Beta Blockers

These are some of the questions which should be asked while consulting a doctor. This will provide a better understanding of beta-blockers.

  • What are the health conditions that can prevent a patient from taking beta-blockers?
  • How long beta-blockers should be taken?
  • How much training or exercise can be done while taking beta-blockers?
  • Will beta-blockers have any effect on a person’s diet?

Conclusion

These drugs have proven to be very effective in the things that they are supposed to do. Experts believe that the patients who have already suffered a heart attack have lowered the risk of another significant attack when treated with beta-blockers. These drugs are generally safe for intake. There can be side effects in some but they are not fatal.

References

  1. https://www.ncbi.nlm.nih.gov/books/NBK532906/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5591796/

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