A nurse is preparing to administer Adenosine to a client with supraventricular tachycardia (SVT). Which client condition should prompt the nurse to question the administration of adenosine?

Adenosine is an ultra–short-acting antiarrhythmic used to terminate supraventricular tachycardia by transiently blocking AV node conduction. Key considerations include AV node suppression, transient asystole risk, bronchospasm in reactive airway disease, and rapid metabolism by erythrocytes and endothelial cells, requiring immediate administration and cardiac monitoring. Rationale: A. Continuous cardiac monitoring is required during adenosine administration to observe for transient asystole or rhythm conversion. This is an expected and essential safety measure, not a contraindication to therapy. B. A history of myocardial infarction is not a contraindication to adenosine use. It is commonly used in patients with ischemic heart disease for SVT termination, provided there is no unstable ventricular rhythm or severe conduction abnormality. C. Penicillin allergy is unrelated to adenosine pharmacology because adenosine is a purine nucleoside, not a beta-lactam antibiotic. This allergy does not increase risk of hypersensitivity or contraindicate administration. D. Adenosine has an extremely short half-life and must be given rapidly, ideally via central or large peripheral IV access, followed by a rapid flush. A central line is appropriate and does not require questioning the order.