Beta-Blockers and Asthma, How They Work, and Which One To Use!

Posted December 4, 2020 by Michael Chamberlain - See Editorial Guidelines

Beta-blockers are often prescribed to patients to treat cardiac conditions, but these medications are often contraindicated in asthma patients. So, what is the relationship and health implications of beta-blockers and asthma?

In this article, we discuss the types of beta-blockers posing the risks for asthma patients, and those that don’t, along with what those risks look like.

First, here’s a quick guideline answer, then we’ll look at more details.

Beta-blockers and asthma: Non-cardio selective beta-blockers block the effects of beta 2 (lung) receptors and asthma medications. This blocks the ability of airways to expand for easier breathing. Taking cardioselective beta-blockers for mild-moderate asthma in low dose is favored, but clinical guidelines remain inconsistent

This is important to understand, and there are more details around this subject, but let’s first recap what beta-blockers are used for.

What Beta-Blockers are for

Beta-Blockers and Asthma

It’s first important to understand the role of beta-blockers and what their intended use is.

Beta-blockers, also known as beta-adrenergic agents, are primarily prescribed for reducing blood pressure and other cardiovascular health conditions.

As the name suggests, this medication blocks the effects of the hormone epinephrine, also known as adrenaline, on beta receptors.

When epinephrine encounters beta receptors, it triggers a response.

There are two main types of receptors called beta 1 receptors, located in the heart, and beta 2 receptors, located in the smooth muscles of the airways and several other areas.

When epinephrine comes into contact with beta-1 receptors, it stimulates its effect on the heart, making the heart beat faster and harder, causing high blood pressure.

High blood pressure is also a symptom of several other cardiovascular health conditions.

So, what needs to be achieved is, these beta-1 receptors located in the heart should be blocked. This is exactly what a beta-blocker does. This is how beta-blockers enable your heart to beat slower with less force, providing a stabilizing effect.

Beta-Blockers are not Prescribed for Asthma

So, looking at their primary use, beta-blockers are not prescribed for asthma or any other respiratory diseases.

The only connection between asthma and high blood pressure is that asthma is a respiratory disease partly linked with high blood pressure in the lungs.

Other than this, asthma is a respiratory health condition, whereas blood pressure is a cardiovascular health condition.

Now that we understand how beta-blockers work let’s understand more about the treatment of asthma.

How Asthma is Treated

The only first-line treatment for asthma is beta-agonists. These medications are also used for other lung conditions.

These medications are known as bronchodilators because they relax airways that are contracted. The name bronchodilators come from the treatment that this medication provides, which is bronchodilation.

When you experience an asthma attack, it causes an involuntary and sudden contraction of the airways called bronchi and bronchioles, making it hard to breathe.

This is what’s called bronchoconstriction. So, asthma patients use bronchodilators, which “dilates” or opens up airways, relaxing the constriction.

Beta-agonists’ focus on relaxing the airways, unlike beta-blockers, that focus on the heart and lung beta receptors.

Beta-Blockers and Asthma

The decision around using beta-blockers with the presence of asthma requires you and your doctor to weigh the risks and benefits of beta-blockers and asthma.

The same goes for patients that are already on beta-blockers for a cardiovascular condition and may have an asthma condition that needs treatment.

There are also other lifestyle factors that need to be considered, such as beta-blockers and coffee, asthma and coffee, or asthma and exercise, and how these types of activities impact your symptoms.

Setting all other effects aside, below is a clearer breakdown of the relationship between asthma and beta-Blockers. 

The Relationships Between Beta-Blockers and Asthma

Beta-Blockers and Asthma

There are two types of beta-blockers, one can favor, and one can hinder the treatment of asthma and its medications

Beta-blockers are not manufactured equally or with the same properties.

As we mentioned above, there are two types of beta receptors as beta-1 (heart) and beta-2 (lungs) receptors. Some beta-blockers are designed to be selective, only for the beta-1 (heart) receptors, to provide a more focused treatment.

This beta-blocker is called cardioselective beta-blockers. They only block the beta-1 receptors, the ones that stimulate the enzymes in the heart. In simple terms, cardioselective beta-blockers will only affect the heart functions.

The other beta-blocker is non-cardio selective, meaning they block both the beta-1 (heart) and beta-2 (lung) receptors. Blocking the receptors located in the lungs has a potential impact on asthma patients who experience breathing problems.

The lung receptors are responsible for relaxing the airways to make breathing easier. This creates the dilemma of using beta-blockers for patients with asthma and is a topic to be discussed with your doctor.

Beta-Blockers can Override Asthma

Non-cardio selective beta-blockers overrides the treatment and control of asthma and asthmatic medications 

The use of asthma medication, such as beta-agonists, is primarily to relax and expand the airways to support easy breathing. This is possible only when receptors in the lungs can exert their effects in the airways.

So, what happens is, when you take a non-cardio selective beta-blocker, receptors are blocked from properly functioning, which includes relaxing airways.

Therefore, a beta-blocker will also constrict and narrow down the airways, just like bronchoconstriction that asthma patients experience. So, in short, non-cardio selective beta-blockers are not ideal for asthma patients. 

On the other hand, if an asthma patient using a bronchodilator also takes a non-cardio selective beta-blocker, the bronchodilator’s effect will also be blocked.

Non-cardio selective beta-blockers completely remove the healing properties of bronchodilators.

In other words, we are taking a medication that will potentially block the life-saving effects of an asthma medication.

Beta-Blockers that can be Effective with Asthma

Cardio selective beta-blockers seem favorable for asthma and its medications.

Cardio selective beta-blockers focus on the receptors in the heart and do not have any real impact on the lungs.

This means that lung receptors can still stimulate and exert functions in relaxing the airways, helping asthma patients avoid bronchoconstriction situations.

The cardioselective beta-blockers that asthma patients can use are as follows:

Are Cardioselective Beta-Blockers Safe for Asthma Patients?

In past years, experts have, in general, recommended avoiding the use of beta-blockers in asthma patients, as it has a high potential of exacerbating asthmatic conditions. 

Studies have since looked at the benefits of cardioselective beta-blockers for patients with cardiovascular and asthmatic health conditions.

In these studies, cardioselective beta-blockers were used on a case-by-case basis in people with asthma. Such usage was confined to a strict dosage and administration.

Again though, clinical guidelines on this usage remain inconsistent and arguable on different grounds. The result is that some national guidelines continue to restrict the use of all types of beta-blockers for patients with asthma.

Even though some studies indicate that the safety of using cardioselective beta-blockers for asthma patients is believed to be favorable if the patient experiences mild to moderate asthma and is prescribed low doses.

But this should strictly be guided by a specialist’s knowledge and recommendations, as the potential risks of cardioselective beta-blockers on asthma is still inconsistent. 

The national review of asthma and deaths (2014) also reminds us that reports of fatalities in the UK increased for asthma patients due to an attack triggered by beta-blockers. Roughly 2% of 195 deaths, meaning 4 deaths of 195 deaths in asthma patients, are believed to have been triggered or affected by beta-blockers or NSAIDs.

Final Thoughts

While this area is still largely unconcluded, it’s probably more important than ever to speak to your doctor about this subject. Every person is unique, and what may work for you may not work for another patient.

Your doctor is more likely to understand your own unique circumstances and can therefore recommend the best course of action for you.

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