A prescriber has ordered propranolol for a client with recurrent ventricular tachycardia. The nurse preparing to administer this drug will be concerned about what in the client's history?

Propranolol is a non-selective beta-adrenergic antagonist that blocks both beta-1 receptors in the heart and beta-2 receptors in the lungs. This medication effectively slows the heart rate and reduces myocardial oxygen demand, but its non-selective nature makes it dangerous for patients with pre-existing reactive airway diseases due to the risk of bronchospasm. A. Propranolol blocks beta-2 receptors located in the bronchial smooth muscle, which normally facilitate bronchodilation. In a patient with asthma, this blockage can trigger severe, potentially fatal bronchoconstriction. Therefore, non-selective beta-blockers are strictly contraindicated for patients with a history of asthma or chronic obstructive pulmonary disease. B. Propranolol is actually indicated for exercise-induced tachyarrhythmias. By inhibiting the sympathetic nervous system's "fight or flight" response, it prevents the catecholamine-driven increase in heart rate that occurs during physical exertion, making this a therapeutic use rather than a cause for nursing concern or contraindication. C. Propranolol is frequently used as an antihypertensive agent. It lowers blood pressure by reducing cardiac output and inhibiting the release of renin from the kidneys. A history of hypertension would be a reason to administer the medication, not a reason for the nurse to be concerned about its safety. D. Emotional stress triggers a sympathetic response that can lead to paroxysmal atrial tachycardia. Propranolol is effective in managing these symptoms by blunting the effects of adrenaline on the heart. Like exercise-induced arrhythmias, this is an appropriate clinical application for a beta-blocker.