Question

What is the site of action of the diuretic Acetazolamide?

(a) Proximal tubule

(b) Glomerulus

(c) Descending loop of Henle

(d) Distal tubule

I have been asked this question during an interview.

My enquiry is from Diuretics in portion Applications of Pharmacokinetic Principles, Diuretics, Drug Concentration and Pharmacologic Response of Drug Biotechnology

Answer 1

Correct answer is (a) Proximal tubule

The best I can explain: Acetazolamide is carbonic anhydrase inhibitor, they work by inhibiting carbonic anhydrous, thus prevents the exchange of H+ ions with sodium and water. The enzyme carbonic anhydrase helps to make H+ ions available so they can be exchanged with sodium and water in the proximal tubules. Inhibition of carbonic anhydrase reduces H+ ion concentration in the renal tubule, as a result, there is increased excretion of bicarbonate, sodium, water, and potassium resorption of water is decreased and urine volume is increased.