What type of drug is furosemide?

• A. Thiazide diuretic
• B. Loop diuretic
• C. Potassium-sparing diuretic
• D. Carbonic anhydrase inhibitor

Answer: (B)

Furosemide is classified as a loop diuretic, which means it acts on the loop of Henle in the kidneys to promote the excretion of sodium, chloride, and water. This class of diuretics is particularly effective in managing conditions such as heart failure and edema due to its potent diuretic effect. Loop diuretics, like furosemide, produce a significant increase in urine output, which helps in lowering blood pressure and reducing fluid overload in patients.

The mechanism of furosemide involves the inhibition of the Na-K-2Cl co-transporter in the ascending loop of Henle, leading to decreased reabsorption of these electrolytes and, consequently, increased urine production. Because of this strong effect, loop diuretics are commonly used in acute settings, such as for the treatment of pulmonary edema.

In contrast, thiazide diuretics act on the distal convoluted tubule and are not as potent as loop diuretics. Potassium-sparing diuretics, on the other hand, help to conserve potassium while promoting diuresis, and carbonic anhydrase inhibitors primarily affect bicarbonate reabsorption in the proximal tubule, making them functionally different from loop diuret