A nurse is caring for a client who has heart failure and has started taking a loop diuretic. Which of the following findings indicates the client is experiencing an adverse effect of the medication?

A. Decreased reflexes: Loop diuretics can cause electrolyte imbalances, particularly hypokalemia and hypomagnesemia. Hypokalemia can lead to neuromuscular changes, including decreased reflexes, muscle weakness, and potentially life-threatening cardiac arrhythmias. This is an adverse effect that requires prompt assessment and intervention. B. Weight gain of 1.4 kg (3 lb): Weight gain in heart failure may indicate fluid retention, but a loop diuretic typically promotes diuresis. A small weight gain of 1.4 kg is not immediately indicative of an adverse effect from the medication itself and may reflect other factors, such as fluid shifts or diet. C. Increased urinary output: Increased urinary output is the intended therapeutic effect of loop diuretics. It indicates that the medication is working to reduce fluid overload rather than an adverse effect. D. Jugular vein distention: Jugular vein distention is a sign of fluid overload in heart failure. While it may indicate insufficient therapeutic response, it is not a direct adverse effect of the loop diuretic. Monitoring and adjusting therapy may be necessary, but it is not a medication-related complication.