The nurse is caring for a client who has started a potassium-sparing diuretic for heart failure 3 days ago. The client reports feeling weak with bouts of nausea and vomiting. Which potential condition is the client at greatest risk for?

A. Hyperkalemia: Potassium-sparing diuretics reduce renal potassium excretion, increasing the risk of elevated serum potassium levels. Early manifestations include muscle weakness, nausea, vomiting, and potential cardiac conduction abnormalities. In a client with heart failure, this risk is heightened due to altered renal perfusion and concurrent medications. B. Hypercalcemia: Potassium-sparing diuretics do not significantly affect calcium reabsorption in the kidneys. Symptoms such as weakness and gastrointestinal upset are not typically related to calcium imbalance with this drug class. Hypercalcemia is more commonly associated with thiazide diuretics. C. Hyperlipidemia: Changes in lipid profiles are not a known adverse effect of potassium-sparing diuretics. These medications primarily influence sodium and potassium handling rather than lipid metabolism. D. Hyperglycemia: Potassium-sparing diuretics do not impair insulin secretion or glucose utilization. Hyperglycemia is more often associated with corticosteroids or certain thiazide diuretics.