From the Guidelines
Adenosine causes bronchoconstriction rather than bronchodilation, particularly in patients with asthma or other reactive airway diseases. When administered, adenosine stimulates adenosine A1 receptors in the lungs, which leads to contraction of bronchial smooth muscle and narrowing of the airways [ 1 ]. This bronchoconstricting effect is significant in patients with asthma, where it can trigger bronchospasm and respiratory distress. The mechanism involves adenosine binding to specific receptors that increase intracellular calcium in airway smooth muscle cells, promoting contraction. Additionally, adenosine can trigger mast cell degranulation, releasing histamine and other inflammatory mediators that further contribute to bronchoconstriction, as indicated by the capacity of adenosine to augment mediator release from mast cells in vivo [ 1 ].
Some key points to consider:
- Adenosine-induced bronchoconstriction in asthmatics may depend on the state of airway mast-cell priming [ 1 ].
- Adenosine challenge may be a useful tool in the differential diagnosis of asthma and COPD in patients of all ages in whom the diagnosis is clinically uncertain [ 1 ].
- The specificity of adenosine bronchoprovocation for asthma, together with the high repeatability of this test, could be useful for epidemiological studies [ 1 ].
- Clinicians should be aware of the bronchoconstricting effect of adenosine when administering it for its other uses, such as treating supraventricular tachycardia, and should have rescue bronchodilators readily available.
From the FDA Drug Label
Adenosine injection administration can cause dyspnea, bronchoconstriction, and respiratory compromise. Adenosine injection should be used with caution in patients with obstructive lung disease not associated with bronchoconstriction (e.g., emphysema, bronchitis). Do not use in patients with bronchoconstriction or bronchospasm (e.g., asthma).
Adenosine bronchoconstricts. It is not recommended for use in patients with bronchoconstriction or bronchospasm, such as those with asthma 2.
From the Research
Adenosine's Effect on Airways
- Adenosine causes bronchoconstriction in asthmatic patients, as shown in studies 3, 4, 5, 6.
- The mechanism of adenosine-induced bronchoconstriction is not fully understood, but it is thought to involve the release of mast cell mediators 6.
- Adenosine is less potent than histamine in producing bronchoconstriction, with higher concentrations required to produce the same effect 3, 4.
- Theophylline, a bronchodilator, can inhibit adenosine-induced bronchoconstriction, suggesting a potential therapeutic target 3.
Role of Adenosine in Asthma and COPD
- Adenosine levels are elevated in the lungs of asthma patients, indicating a potential role in the pathogenesis of the disease 5.
- Adenosine can induce bronchoconstriction in patients with chronic obstructive pulmonary disease (COPD) as well as asthma 5, 7.
- Animal studies have shown that elevating adenosine levels can induce a pulmonary phenotype with features of asthma and COPD 5.
Clinical Implications
- Adenosine should be used with caution in patients with asthma or COPD, as it can precipitate severe bronchospasm 7.
- Even patients without a history of pulmonary disease can experience severe bronchospasm after adenosine administration 7.
- Physicians should be alert to the presence of objective signs of respiratory distress after adenosine administration and provide immediate treatment if necessary 7.