Drug affecting positive free water
clearance without affecting negative free
water clearance -
a) Loop diuretics
b) Thiazides
c) Acetazolamide
d) Amiloride
Correct Answer - B
Ans. b. Thiazides
Loop diuretics abolishes the cortico-medullary osmotic gradient and
blocks positive as well as negative free water clearance.
Thiazides decrease positive free water clearance without affecting
negative free water clearance.