From the Guidelines
Beta blockers should be used with caution in patients with asthma, and alternative medications should be considered first, due to the risk of bronchospasm and worsening of asthma symptoms. These medications work by blocking beta-adrenergic receptors, including beta-2 receptors in the lungs that help keep airways open. When blocked, this can cause airway constriction, potentially triggering or worsening asthma symptoms 1. If a beta blocker is absolutely necessary for conditions like heart failure or hypertension, cardioselective beta blockers such as metoprolol, bisoprolol, or atenolol are preferred as they primarily target beta-1 receptors in the heart with less effect on the lungs. However, even cardioselective agents can lose their selectivity at higher doses.
Some key points to consider when using beta blockers in patients with asthma include:
- Starting with a low dose and carefully monitoring for respiratory symptoms
- Keeping rescue inhalers readily available
- Ensuring optimal asthma management before starting any beta blocker
- Considering alternative medications first, especially in patients with severe or poorly controlled asthma
- Being aware of the potential for beta blockers to worsen asthma symptoms, especially in patients with a history of asthma or chronic obstructive lung disease 1.
In terms of specific beta blockers, beta-1 selective beta blockers are preferred in patients with asthma, and should be initiated at a low dosage 1. It's also important to note that beta blockers without intrinsic sympathomimetic activity are preferred, especially beta-1 blockers such as sustained-release metoprolol succinate, bisoprolol, or carvedilol, due to their mortality benefit in patients with heart failure and systolic dysfunction 1.
From the FDA Drug Label
In asthmatic patients, metoprolol reduces FEV 1 and FVC significantly less than a nonselective beta-blocker, propranolol, at equivalent beta 1-receptor blocking doses Pulmonary function studies have been conducted in healthy volunteers, asthmatics, and patients with chronic obstructive pulmonary disease (COPD). Doses of bisoprolol fumarate ranged from 5 to 60 mg, atenolol from 50 to 200 mg, metoprolol from 100 to 200 mg, and propranolol from 40 to 80 mg In some studies, slight, asymptomatic increases in airways resistance (AWR) and decreases in forced expiratory volume (FEV 1) were observed with doses of bisoprolol fumarate 20 mg and higher, similar to the small increases in AWR also noted with the other cardioselective beta-blockers.
Beta blockers and asthma:
- Beta 1-selective blockers like metoprolol and bisoprolol may be safer for patients with asthma compared to nonselective beta blockers.
- Caution is still needed when prescribing beta blockers to patients with asthma, as they may still experience some decrease in lung function.
- Monitoring of lung function is recommended when using beta blockers in patients with asthma 2 3.
- Key points to consider:
- Beta 1-selective blockers may be a better option for patients with asthma.
- Patients with asthma should be monitored closely when taking beta blockers.
- Nonselective beta blockers should be avoided in patients with asthma if possible.
From the Research
Beta Blockers and Asthma
- The use of beta blockers in patients with asthma is a topic of ongoing debate, with some studies suggesting that cardio-selective beta blockers may be safe to use in certain cases 4, 5.
- Non-selective beta blockers, on the other hand, are generally considered to pose a higher risk of exacerbating asthma symptoms 4, 6.
- Some studies have suggested that beta blockers may even have beneficial effects on airway inflammation and hyperresponsiveness in certain patients with asthma 7, 8.
- However, the evidence is not yet conclusive, and more research is needed to fully understand the relationship between beta blockers and asthma 4, 8.
Types of Beta Blockers
- Selective beta 1-blockers, such as metoprolol and atenolol, may be safer to use in patients with asthma than non-selective beta blockers 5, 6.
- Alpha- and beta-blockers, such as carvedilol, may also pose a lower risk of exacerbating asthma symptoms 6.
- Dual alpha- and beta-blockers, hydrophilic and lipophilic beta blockers, may be safer options for asthmatic patients 6.
Clinical Implications
- Clinicians should exercise caution when prescribing beta blockers to patients with asthma, and consider alternative treatment options whenever possible 4, 5.
- The selection of beta blockers should be based on the individual patient's needs and medical history, taking into account the potential risks and benefits of different beta blocker classes 6.
- Further research is needed to fully understand the relationship between beta blockers and asthma, and to inform evidence-based clinical decision-making 4, 8.