What effect may antihistamines have on patients with asthma?

Antihistamines have the potential to exacerbate asthma symptoms due to their drying effects on mucosal surfaces. These medications work by blocking histamine receptors, which can lead to reduced mucus production in the airways. While this might seem beneficial, the resulting dryness can irritate the respiratory tract and make it more susceptible to inflammation and bronchoconstriction, particularly in individuals with asthma. This is particularly true for first-generation antihistamines, which can cause more sedation and have pronounced anticholinergic effects that contribute to bronchial secretions becoming thickened and less mobile.

In contrast, although some may believe that antihistamines can improve symptoms by reducing allergic reactions that may trigger asthma, their drying effect can lead to adverse reactions in sensitive patients. Therefore, understanding the dual nature of how these agents interact with respiratory conditions is crucial for managing asthma effectively.