PANCE Cardiology Practice Test

The main concept is that blocking beta-adrenergic receptors can worsen asthma. In the lungs, beta-2 receptors normally cause bronchodilation when stimulated. A beta-blocker that blocks both beta-1 and beta-2 receptors (nonselective) removes this bronchodilatory influence, making bronchial smooth muscle more prone to constrict and triggering or worsening asthma symptoms. Because of that, beta blockers are avoided in asthma patients. If a beta blocker is absolutely necessary, a cardioselective agent that primarily blocks beta-1 receptors (with little effect on beta-2) can be considered at the lowest effective dose, but still with caution and close monitoring for bronchospasm. In contrast, the other classes listed do not inherently provoke bronchoconstriction: ACE inhibitors can cause cough due to irritation but not bronchospasm; calcium channel blockers and diuretics do not directly impair bronchial dilation and are generally usable depending on the clinical scenario.