A nurse is preparing to administer verapamil by IV bolus to a client who is having cardiac dysrhythmias. For which of the following adverse effects should the nurse monitor when giving this medication?

Verapamil is a non-dihydropyridine calcium channel blocker that decreases myocardial contractility and slows atrioventricular conduction. Major concerns include hypotension, bradycardia, AV block, and decreased cardiac output, especially with rapid IV administration affecting vascular smooth muscle and cardiac conduction. Rationale: A. Verapamil causes vasodilation and reduced myocardial contractility, leading to decreased systemic vascular resistance and blood pressure. Rapid IV bolus increases risk of significant hypotension, requiring continuous hemodynamic monitoring to prevent syncope, shock, or compromised organ perfusion. B. Ototoxicity is associated with medications like aminoglycosides and loop diuretics affecting the auditory nerve. Verapamil does not impact cochlear function or vestibular structures, making this adverse effect unrelated to calcium channel blocker pharmacodynamics. C. Muscle pain is commonly linked to statins causing myopathy due to muscle fiber breakdown. Verapamil does not interfere with skeletal muscle metabolism or cause creatine kinase elevation, so this is not an expected or relevant adverse effect. D. Hyperthermia is typically related to malignant hyperthermia or heat-related illness involving thermoregulation dysfunction. Verapamil does not affect central temperature regulation or skeletal muscle calcium release in a manner that would produce elevated body temperature.