A new diuretic is being studied in human volunteers. Compared with placebo, the new drug increases urine volume, decreases urinary Ca2+, increases body pH, and decreases serum K+. If this new drug has a similar mechanism of action to an established diuretic, it probably
blocks the NaCl cotransporter in the DCT
blocks aldosterone receptors in the CT
inhibits carbonic anhydrase in the PCT
inhibits the Na/K/2Cl cotransporter in the TAL
The effects described are typical of thiazide diuretics, which inhibit the Na/Cl cotransporter in the distal convoluted tubule. This action facilitates reabsorption of Ca2+, which is the basis for the use of thiazides in nephrolithiasis, and which can result in hypercalcemia. The increased load of Na+ in the collecting tubules leads to increased excretion of both K+ and Hi, so hypokalemia and alkalosis may occur.
C.V.S