Question

What is the site of action of the loop diuretics?

(a) Proximal tubule

(b) Glomerulus

(c) Ascending loop of Henle

(d) Distal tubule

The question was posed to me in an internship interview.

My question is from Diuretics topic in division Applications of Pharmacokinetic Principles, Diuretics, Drug Concentration and Pharmacologic Response of Drug Biotechnology

Answer 1

Correct answer is (c) Ascending loop of Henle

Explanation: Loop diuretics act on the ascending limb of the loop of Henle to inhibit sodium and chloride resorption. These also increase renal prostaglandins, resulting in the dilation of blood vessels and reduced peripheral vascular resistance. These cause loss of water reduces blood pressure, reduced pulmonary vascular resistance, reduced systemic vascular resistance and central venous pressure.