What outcome indicates effectiveness of furosemide when treating heart failure?

• A. Promote vasodilation
• B. Reduction of preload
• C. Decrease in afterload
• D. Increase in contractility

Answer: (B)

The key idea is how diuretics help in heart failure by easing the heart’s filling pressures. Furosemide is a loop diuretic that increases urine output, which lowers intravascular volume and venous return to the heart. This reduces end-diastolic volume and pressure—i.e., preload. When preload drops, the ventricles aren’t as stretched before contraction, which lowers pulmonary and systemic congestion, improves shortness of breath, and reduces edema. That improvement in filling pressures is the primary and most direct measure of furosemide’s effectiveness.

Vasodilation and afterload reduction are beneficial in heart failure, but they’re not the main action of a diuretic like furosemide. Increasing contractility is not an effect of a diuretic and isn’t how this medication works.