Which class of antianginal agent is contraindicated in asthma patients?

Non-selective beta-blockers are contraindicated in asthma patients due to their mechanism of action and potential side effects. These medications block both beta-1 and beta-2 adrenergic receptors. While the blockade of beta-1 receptors primarily affects the heart, leading to decreased heart rate and contractility beneficial in managing angina, the blockade of beta-2 receptors can lead to bronchoconstriction. This can exacerbate asthma symptoms and potentially trigger an asthmatic attack, making it unsafe for individuals with reactive airway disease.

In contrast, selective beta-blockers predominantly target beta-1 receptors and are considered safer for asthma patients, as they have minimal impact on beta-2 receptors. Calcium channel blockers work differently by relaxing vascular smooth muscle and reducing myocardial oxygen demand without impacting bronchial tone, thus posing no direct contraindication for asthmatic patients. Nitrates primarily act as vasodilators and also do not have adverse effects on bronchial function. Thus, the use of non-selective beta-blockers in asthma is discouraged due to the risk of triggering bronchoconstriction, making them unsuitable for patients with this condition.