From the Guidelines
If a patient starts wheezing after beginning propranolol, they should stop taking the medication immediately and contact their healthcare provider right away. This is considered an urgent medical situation that requires prompt attention. Wheezing after starting propranolol likely indicates bronchospasm, a potentially serious adverse effect that occurs because propranolol blocks beta-2 receptors in the lungs that normally help keep airways open. This blockade can cause airway constriction, particularly in patients with underlying respiratory conditions like asthma or COPD.
- Key points to consider:
- Propranolol is a non-selective beta blocker, which means it can affect both beta-1 and beta-2 receptors in the body 1.
- Beta-2 receptors are primarily found in the lungs and are responsible for dilating airways, so blocking them can lead to bronchospasm and wheezing 1.
- Patients with a history of asthma, COPD, or other respiratory conditions are at higher risk for this adverse effect and should inform their doctor before starting any beta blocker 1.
- The healthcare provider may switch the patient to a different medication, possibly a cardioselective beta blocker like metoprolol or atenolol, which has less effect on the lungs 1.
- In some cases, temporary discontinuation of propranolol may be necessary, such as in the setting of significantly reduced oral intake or if the patient has wheezing that requires treatment 1. While waiting to speak with their healthcare provider, patients experiencing severe breathing difficulties should seek emergency medical attention by calling 911 or going to the nearest emergency room.
From the FDA Drug Label
Nonallergic Bronchospasm (e.g., Chronic Bronchitis, Emphysema): In general, patients with bronchospastic lung disease should not receive beta-blockers. Propranolol should be administered with caution in this setting since it may provoke a bronchial asthmatic attack by blocking bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta-receptors
The patient should stop taking propranolol and seek medical attention immediately, as the medication may be provoking a bronchial asthmatic attack.
- The patient's wheezing may be a sign of bronchospasm, which can be exacerbated by propranolol.
- Treatment for bronchospasm, such as isoproterenol or aminophylline, may be necessary 2.
From the Research
Patient Experience with Propranolol
- A patient who started propranolol yesterday and is experiencing wheezing today may be at risk of bronchoconstriction, as propranolol is a non-selective beta blocker that can cause airway constriction 3, 4, 5, 6.
- The patient's symptoms could be similar to those experienced by asthmatic patients who have taken propranolol, which can lead to severe bronchoconstriction and even death in extreme cases 3.
Studies on Propranolol and Airway Function
- A study published in 1981 found that propranolol worsened pulmonary function in patients with chronic obstructive pulmonary disease (COPD), indicating that the drug may have a deleterious effect on airway function in non-asthmatic patients 4.
- Another study from 1982 found that propranolol caused pronounced bronchoconstriction in six out of 14 asthmatic patients, highlighting the potential risks of using this medication in patients with asthma 5.
- A 1984 study compared the effects of propranolol and metoprolol on ventilation in patients with asthma, bronchitis, and emphysema, and found that propranolol was more likely to cause wheezing and bronchoconstriction, especially in patients with reversible airways disease 6.
Potential Treatments for Propranolol-Induced Bronchoconstriction
- A 1997 study found that inhaled frusemide could attenuate propranolol-induced bronchoconstriction in patients with stable mild asthma, suggesting a potential treatment option for patients who experience wheezing after taking propranolol 7.
- Patients who experience wheezing after taking propranolol should seek medical attention immediately, as this can be a sign of a serious allergic reaction or bronchoconstriction 3, 4, 5, 6.