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?

Choice A reason: Decreased reflexes indicate hypokalemia, a common adverse effect of loop diuretics such as furosemide. Loop diuretics cause significant potassium and magnesium loss, which can impair neuromuscular function and lead to decreased reflexes, muscle weakness, and arrhythmias. Choice B reason: Weight gain of 1.4 kg (3 lb) suggests fluid retention, which is a sign of worsening heart failure rather than a direct adverse effect of the diuretic. If the diuretic is effective, weight should decrease due to fluid loss. Choice C reason: Increased urinary output is an expected therapeutic effect of loop diuretics. It indicates the medication is working to reduce fluid overload. Choice D reason: Jugular vein distention is a sign of fluid overload and worsening heart failure, not a direct adverse effect of loop diuretics. Effective diuretic therapy should reduce JVD.