Beta-blockers are prescription drugs commonly used to manage cardiovascular diseases, including heart failure, congenital heart disease, cardiomyopathy, hypertension, and other conditions that may benefit from their use. If you have asthma and another comorbidity (a secondary condition co-occurring with the primary one) that may require beta-blocker medication, your doctor may exercise caution before prescribing beta-blockers due to possible side effects on your asthma symptoms.
Beta-blockers can be beneficial if you have asthma and heart disease as comorbidity; however, some people are not recommended beta-blockers, especially when there are disagreements between differing guidelines for this treatment. So, are beta-blockers safe for asthma?
In this comprehensive article, you'll learn how beta-blockers function, what types of beta-blockers may be safe if you have asthma, including the possible risks of using certain beta-blockers.
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Also known as beta-antagonists or beta-adrenergic blocking agents, beta-blockers are a type of medication first developed and used in the 60s that help slow the heart rate and moderate blood pressure. As the term suggests, they work by blocking the "beta receptors" that bind epinephrine or adrenaline.
Adrenaline is the hormone that is triggered when you experience danger or stress. Once this hormone is released, it latches on to tiny proteins called beta receptors to cause your body to respond. This reaction may cause your heart to beat faster and your blood pressure to increase, and thus can be harmful if you have heart disease or hypertension.
Beta-blockers work by binding themselves to beta receptors, preventing the impact of adrenaline and the subsequent reaction on your body.
Your doctor may also prescribe beta-blockers if you have other conditions such as migraines, anxiety disorders, glaucoma, or an overactive thyroid.
If you have asthma and another medical condition that can benefit from a beta-blockers prescription, your doctor will help you assess the possible risks and decide whether it's a good fit for you. Since beta-blockers regulate blood pressure and heart function, they can help people with asthma reduce attacks of shortness of breath, i.e., dyspnea associated with heart diseases, possibly improving symptoms also associated with asthma.
Beta receptors are found in both heart and lung tissue. Beta-blockers are used to treat heart disease or hypertension, but beta-agonists (bronchodilators) are coupled with inhaled steroids for asthma treatment. Instead of blocking the beta receptors, beta-agonists activate the receptors just as epinephrine does, causing the airways to relax.
This treatment improves asthma symptoms by allowing for an easier flow of air.
However, when beta-blockers work on lung tissue, they cause the airways to narrow or contract, which might make it difficult for you to breathe. If you have asthma or any other pulmonary disease, this can cause dyspnea, among other side effects, such as anxiety and wheezing.
In rare cases, these beta-blocker medications may also cause asthma exacerbation. However, studies¹ indicate that these side effects depend on the type of beta-blockers, dosage, and whether the use is chronic.
If you have asthma and are on any beta-adrenergic blocking agents medication, like propranolol, it's important to talk to your doctor if you experience any of the above symptoms. Sometimes, your healthcare provider can cut the beta-blocker dosage you're currently taking to lessen the symptoms. They may also suggest a change in the prescription that has a more negligible effect on asthma symptoms.
To understand this, you'll first need to learn the types of beta-blockers. Although no definitive research indicates that any kind of beta-adrenergic blocking agent is 100% safe, studies¹ have found that selective beta-blockers are safer than non-selective beta-blockers in people with asthma or lung disease.
There are three types of beta receptors — beta-1 receptors, beta-2 receptors, and beta-3 receptors.
While both beta-1 and beta-2 receptors can be found in the heart and lungs, beta-1 receptors are predominant in the heart tissue, while beta-2 receptors make up most of the pulmonary lung tissue. Beta-3 receptors are responsible mainly for the function of fat cells and are not clinically relevant to the heart and lungs.
As the name suggests, non-selective beta-antagonists act on beta-1 and beta-2 receptors, regardless of where they are found in the body. Therefore, if you have asthma or any pulmonary condition like COPD, these non-selective beta-blockers can significantly worsen your symptoms.
One study² suggests that propranolol, a non-selective beta-blocker, can have an adverse effect on asthmatic people.
Other types of non-selective or first-generation beta-blockers drugs include:
In most cases, your medical provider is unlikely to recommend a non-selective beta-blocker if you have asthma unless the benefits you receive to treat other conditions outweigh the risks. Fortunately, modern medicine has invented beta-blockers that are safer for people with asthma.
Selective beta-blockers act predominantly on beta-1 receptors only; hence, the name selective. They are also commonly known as cardioselective since they predominantly work on beta-1 receptors that are more prevalent in the heart than in the lung.
Cardioselective beta-blockers might be a safer option if you have asthma and a heart condition as comorbidity. Cardioselective beta-blockers have a minimal effect on the airways, hence an insignificant risk for asthma symptoms.
A medical study involving more than thirty-five thousand people found no relevant negative implications of the cardioselective beta-blockers on asthma symptoms.
Some of the selective beta-blockers that your doctor may recommend are:
Metoprolol succinate (Toprol XL)
Bisoprolol Fumarate (Zebeta)
Although selective beta-blockers are considered safer for people with asthma, they're only recommended in low dosages and only when other therapeutic options aren't effective or unavailable. Also, different people might have varied results depending on sensitivity to the beta-blockers.
Even when using selective beta-blockers, you must discuss with your doctor if you notice worsening asthma symptoms.
Generally, all beta-blockers have possible side effects, whether you have asthma or not. For people without asthma or other lung diseases, the side effects rarely affect the body's respiratory function. Some of the possible effects of beta-blockers include, but are not limited to:
Dizziness or lightheadedness due to low blood pressure
Altered blood circulation, causing cold hands and feet
Minimal weight gain
Low blood sugar
Modern research in medicine has developed improved beta-blockers that reduce these risks by selectively acting on specific receptors in certain tissues rather than in the whole body.
It's possible to combine asthma medications with certain beta-blockers safely. While additional research is needed, one study³ found that beta-blockers can potentially render inhalers ineffective, leading to asthma exacerbations.
Salbutamol, a beta-2 agonist, is used to manage asthma symptoms. One study⁴ involving bisoprolol (cardioselective beta-blocker) and salbutamol found no significant effect of the beta-blocker on the effectiveness of salbutamol.
It's not recommended to take propranolol if you have asthma. This non-selective beta-blocker can potentially cause serious bronchospasm in people with asthma. Other studies⁵ have also linked propranolol and other 1st generation beta-blockers to increased airway resistance.
However, another small randomized trial⁶ suggested that people with mild to moderate asthma may not be affected by propranolol.
Metoprolol is a type of cardioselective beta-blocker that your doctor may prescribe to improve angina or hypertension. If you have asthma, it's relatively safe as it won't interfere with beta-2 receptors that are found in the lung.
Nevertheless, always discuss your case with your doctor. A 2014 review involving 32 studies⁷ suggests that about one in eight people with asthma showed a 20% drop in FEV1 after using selective beta-blockers. Forced expiratory volume (FEV1) is the amount of air you can expire in one second with maximal effort and is a good indicator of asthma status.
Nonetheless, in most cases, the FEV1 will stabilize within two weeks.
Apart from the risk related to beta-blockers in people with asthma, some other conditions or health concerns may discourage using beta-blockers. These include:
Senior citizens above 60 years old
People with thyroid, kidney, or liver conditions
Those allergic to the medication or one of its ingredients
It's always advisable to discuss all your conditions with your doctor, so they can prescribe the appropriate medication that won't have significant side effects on your current condition.
Beta-blockers are common medications for heart disease, hypertension, and other health conditions. Beta-blockers work by binding beta receptors to prevent the attachment of adrenaline (epinephrine). The impact of epinephrine is minimized, thus balancing the blood pressure and heart rate.
If you have asthma, there are various risks associated with taking beta-blockers. However, selective beta-blockers have shown a less negative effect on asthma symptoms than non-selective beta-blockers. Therefore, your doctor may recommend these cardioselective beta-blockers to help manage comorbidity.
When you start using beta-blockers, monitor any asthma symptoms. If you notice that the medication is acting as a trigger for asthma attacks, talk to your doctor. They may lower the dose, change medication, or try another method to treat your condition.