Beta-Blockers: Uses, Types, Side-Effects, and Precautions

What are Beta-Blockers?

Beta-Blockers are specialized drugs that are used to reduce blood pressure by inhibiting the action of a hormone called “Epinephrine or Adrenaline” that affects stress parameters.

It lowers blood pressure and simultaneously dilates the veins and arteries and improves the rate of blood flow.

This medication, not only affects blood pressure but also tremors, anxiety disorders, glaucoma (a combination of eye conditions where the damage in the optic nerve causes blindness), hyperthyroidism (excessive production of thyroid hormone).

The other commonly used terms for Beta-Blockers are Beta-adrenergic blocking agents, Beta-adrenergic antagonists, and Beta-antagonists. 

Uses of Beta-Blockers

Beta Blockers are mainly concerned with the treatment of cardiovascular diseases and other conditions like myocardial infarction, tachycardia, hypertension, congestive heart failure, hyperthyroidism, coronary heart disease, cardiac arrhythmias, tremors, aortic dissections, glaucoma, portal hypertension, migraine prophylaxis, etc…

Sometimes it can also be used to treat rare conditions like Long QT syndrome (a heart rhythm disorder) and Hypertrophic Obstructive Cardiomyopathy (a condition where cardiac muscles are abnormally thick). 

The Beta-Blockers used for patients with Congestive Heart Failure are,

  • Bisoprolol
  • Carvedilol 
  • Metoprolol succinate

Other commonly used Beta-Blockers are,

  • atenolol (Tenormin)
  • propranolol (Inderal LA)
  • metoprolol (Lopressor, Toprol XL)
  • esmolol (Brevibloc)
  • nadolol (Corgard)
  • nebivolol (Bystolic)
  • carteolol (Cartrol)
  • acebutolol (Sectral)
  • bisoprolol (Zebeta)

Many athletes and musicians consume these drugs for an anxiolytic effect (to relieve anxiety) and their inhibitory effect on the Sympathetic Nervous System.

Beta-Blockers are usually administered in three main forms,

  • Oral
  • Ophthalmic
  • Intravenous 

The means of administration often depends on the 

  • The perspicacity of the illness
  • Chronicity of the disease
  • Disease type (topical use in glaucoma). 

Types of beta receptors in the body

There are three types of Beta receptors, they are

  • BETA 1 – Present in Heart and regulates cardiac activity.
  • BETA 2 – Present in diverse locations in the body and controls various metabolic activity and causes smooth muscle relaxation.
  • BETA 3 – Involved in fat cells breakdown mechanism

Beta-Blockers function by inducing their effects on these receptors, thus, they are essential drugs and are considered to be the first line of treatments in various diseases.

Side effects of Beta-Blockers

Since these drugs work by the inhibitory effects of the receptors in the body, they have a variety of side effects like

Commonly you may experience,

  • Bradycardia (slow heartbeat)
  • Hypotension (low blood pressure)
  • Fatigue
  • Nausea and vomiting
  • Weakness 
  • Constipation
  • Abdominal discomfort
  • Edema (fluid retention)
  • Dementia (memory loss)
  • Cold feet and hands
  • Diarrhea 

Infrequently, you may experience:

  • Shortness of breath
  • Depression
  • Insomnia
  • Decreased libido

If you accidentally consume a larger dose than recommended, you may experience:

  • Shortness of breath
  • Dizziness
  • Arrhythmias
  • Perplexity

What precautions should be taken?

Patients must not hesitate to confess to their doctors about their medical history, especially when they suffer from one of the below

  • Bronchospasm – occurs when bronchial tubes i.e airways undergo spasms and contract 
  • Asthma
  • Slow heart rate
  • Peripheral heart disease 
  • Heart failure

If you are an addict or if you use drugs like cocaine, you must disclose it to your physician to avoid further complications.  

If you are diabetic, especially Hypoglycemic, you must keep a regular check on your blood sugar level while using Beta-Blockers.

A proper prescription must be followed during the pregnancy while using this drug.

While one is stopping the usage of Beta Blockers, you must have in mind that it must not be suddenly withdrawn. If it is suddenly brought to a halt, it can cause various risks and even turn out to be fatal. So, kindly follow your physician’s advice with the utmost attention.

Frequently Asked Questions

Mention a few interactions of Beta-Blockers.

Just like other drugs, Beta-Blockers can also interact with various other drugs like,
Anti-psychotics (treats mental disorders)
Anti-arrhythmics (counteracts irregular heartbeats)
Anti-hypertensives (lowers Blood Pressure level)
Mefloquine (prevents malaria)
Clonidine (treats migraine and high blood pressure level)

How do Beta-Blockers work? What is its mechanism?

They are often called beta-adrenergic blockers due to their inhibitory action on the hormone Adrenaline.

The binding of Beta-Blockers to Beta 1 and Beta 2 receptors causes inhibition of chronotropic (regulation of heart rate) and ionotropic (muscular contractions) effects, thereby causing negative effects.

Hence, muscular contractions of cardiac muscles are reduced thus reducing the heart rate. 

Can the consumption of Beta-Blockers affect sleep?

Yes, Beta-Blockers have adverse effects on another hormone called “Melatonin” which is responsible for the sleep-wake cycle. Beta-Blockers lower the secretion of melatonin and cause insomnia in some patients.

What are the specific effects of these drugs?

Apart from the common side effects mentioned above, there are few more effects of these drugs as they have a wide range of physiologic effects.
– Few Beta-Blockers cross BLOOD BRAIN BARRIER and can cause insomnia, sleep cycle changes, even nightmares in a few.
Sotalol is a type of beta-blocker that blocks the potassium channels in the heart and causes QT prolongation.
Carvedilol may increase fluid retention and causes edema in few patients
– All the Beta-Blockers commonly carry a risk of heart blocks in patients especially in those with cardiac issues.

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