Beta-Adrenoreceptor Blocking Agents - An Overview

Introduction:

Beta-adrenoreceptor blocking agents are the most common drugs the cardiologist prescribes for heart conditions like high blood pressure, chest pain, heart failure, etc. They have other names also, which are beta blockers, beta-antagonists, beta-adrenergic blocking agents, and beta-adrenergic antagonists.

What Are Beta-Adrenoreceptor Blocking Agents?

Beta-adrenoceptor-blocking agents are medications that inhibit the activity of substances like adrenaline on the nerve cells and cause blood vessels to relax and widen. This improves blood flow and reduces blood pressure and heart rate. These medicines are used to treat high blood pressure, chest pain (angina), irregular heartbeat (arrhythmia), congestive heart failure, and a variety of other disorders. They can also reduce the size of certain vascular tumors, such as hemangiomas. These medicines are also known as beta-blockers or beta-adrenergic antagonists.

What Are the Side Effects of Beta-Adrenoreceptor Blocking Agents?

Beta-adrenoreceptor blocking agents are the most commonly used medications in the medical field, and these are generally well tolerated. The side effects include:

• Bradycardia (slow heart rate).

• Fatigue.

• Dizziness.

• Depression.

• Memory loss.

• Insomnia (inability to sleep).

• Impotence.

• Cold limbs.

The least common side effects are:

• Severe hypotension (low blood pressure).

• Heart failure.

• Acute bronchospasm.

• Hepatotoxicity (liver damage).

What Are the Uses of Beta-Adrenoreceptor Blocking Agents?

The beta-adrenoreceptor blocking agent is primarily used for diseases related to the heart. However, it can be used to treat several diseases other than those related to the heart. The uses are listed below:

1. Angina (Chest Pain): These medicines slow down the heart rate and decrease the oxygen demand of the heart. Therefore, lowers the frequency of angina attacks.

2. Hypertension (High Blood Pressure): These medicines are extremely helpful in the treatment of hypertension. They lower blood pressure in conjunction with other medicines like ACE inhibitors (Ramipril) and calcium channel blockers (Amlodipine).

3. Heart Attacks: For those individuals who suffered heart attacks in the past, these medications can help to minimize the risk of another heart attack. For these patients, beta-adrenoreceptor-blocking agents are generally prescribed for lifelong usage.

4. Irregular Heartbeat: In atrial fibrillation (AF) patients, beta-adrenoreceptor blocking agents control irregular heartbeats or arrhythmias. These medications slow the heart rate, and the symptoms which are caused by AF, such as palpitations and fatigue, are greatly improved.

5. Heart Failure: The beta-adrenoreceptor blocking agent can increase the life expectancy in heart failure patients where heart failure is caused by impaired left ventricle contraction. The left ventricle is the primary pump chamber of the heart. The cardiologists suggest that all the patients associated with left ventricular impairment should take these medications, irrespective of the severity of symptoms, as a part of the treatment plan, including ACE inhibitors and aldosterone inhibitors.

6. Coronary Artery Disease: Coronary artery disease (CAD), also known as coronary heart disease, occurs when the coronary arteries become too narrow or when cholesterol deposits form in the walls. The coronary arteries are the blood channels that feed the heart with oxygen and blood. Beta-adrenoreceptor-blocking agents help to lower blood pressure and heart rate, particularly in those who have already had a heart attack.

7. Enlarged Heart or Cardiomyopathy (Hypertrophic Obstructive Cardiomyopathy): Heart conditions like an increase in the size of the heart can be treated with beta-adrenoreceptor blocking agents.

8. Portal Hypertension: Portal hypertension is generally increased pressure in the portal venous system. This condition can also be treated with a beta-adrenoreceptor blocking agent.

9. Migraine (For Preventing Migraine): Beta- adrenoreceptor blocking agents can be used to prevent migraine.

What Are the Other Uses of Beta-Adrenoreceptor Blocking Agents?

Apart from the uses mentioned above, these medicines are also used in the following conditions:

1. Anxiety: Anxiety can be reduced by beta-adrenoreceptor-blocking agents. These medications block the effects of stress hormones. Due to this, the symptoms like trembling and sweating get reduced. However, the Food and Drug Administration (FDA) has not approved the use of these medications for anxiety.

2. Glaucoma: Glaucoma is an eye condition in which pressure builds up within the eye due to fluid build-up. This condition causes vision loss.

3. Essential Tremors: Propranolol can be used to treat hand tremors (shaking of hands).

4. Hyperthyroidism: Symptoms of hyperthyroidism, like tremors and rapid heart rate, can be treated with beta-adrenoreceptor blocking agents.

How Does Beta-Adrenoreceptor Blocking Agents Work?

Beta adrenoreceptor-blocking agents are drugs that prevent the release of the stress hormones adrenaline and noradrenaline in certain regions of the body. This slows the heart rate and lessens the force with which blood is pushed around in the body.

Beta-blockers can also prevent the kidneys from generating angiotensin II. Angiotensin II is a receptor blocker that relaxes the veins and arteries, lowering blood pressure and making it easier for the heart to pump blood. As a result, the blood pressure will be decreased.

What Are the Types of Beta-Adrenoreceptor Blocking Agents?

There are two types of beta-adrenoreceptor blocking agents:

• Non-Selective: The non-selective type includes propranolol, which works to block adrenaline, and noradrenaline in the heart along with the other parts of the body. In addition, this action can result in unpleasant side effects such as chilled hands and an increased risk of asthma attacks.

• Selective: Most of the time, cardiologists prefer selective beta-blockers, such as atenolol and bisoprolol, because their activity primarily affects the heart and has less significant effects in other areas of the body.

When Can Beta-Adrenoreceptor Blocking Agents Not Be Given?

Beta-adrenoreceptor blocking agents can not be given in every type of heart condition. There are some conditions where these medications can not be given. These are:

• Low blood pressure (hypotension).

• Problems with heart rhythm.

• Slow heartbeat.

In addition, in conditions like asthma or other lung diseases, beta blockers can sometimes provoke severe attacks of asthma. Therefore, these are not prescribed in patients diagnosed with either asthma or other lung diseases.

What Are the Examples of Beta-Adrenoreceptor Blocking Agents?

• Acebutolol.

• Atenolol.

• Betaxolol.

• Bisoprolol.

• Carvedilol.

• Esmolol.

• Labetalol.

• Metoprolol.

• Nadolol.

• Nebivolol.

• Penbutolol.

• Pindolol.

• Propranolol.

• Sotalol.

• Timolol.

Conclusion

To conclude, beta-adrenoreceptor-blocking agents are the drugs primarily used for the treatment of high blood pressure. However, they are prescribed for several other heart conditions and conditions not related to the heart, like tremors, migraine, and hyperthyroidism. They are considered safe to use and are generally well tolerated.