Which medication is used to reduce fluid volume in heart failure?

• A. Digoxin
• B. Lisinopril
• C. Hydralazine
• D. Furosemide

Answer: (D)

The main concept is reducing fluid overload in heart failure by promoting diuresis to lower the volume the heart has to handle. Furosemide is a loop diuretic that blocks the Na-K-2Cl transporter in the thick ascending limb of the nephron, leading to large amounts of sodium and water being excreted in the urine. This diuresis decreases preload, relieves edema, and reduces pulmonary congestion, giving rapid symptom relief in volume-overloaded heart failure.

Digoxin mainly improves cardiac output by increasing contractility, but it doesn’t directly remove excess fluid. Lisinopril (an ACE inhibitor) helps by afterload reduction and neurohormonal modulation, which can indirectly reduce fluid buildup over time, but its primary action isn’t diuresis. Hydralazine is another afterload reducer without a direct diuretic effect. Therefore, the medication that most directly reduces fluid volume is furosemide.