<prompt> Which drug abolishes coicomedullary osmotic gradient ?FurosemideThiazideSpironolactoneTriamterene  <response>: Ans. isai.e., Furosemide Ref. KDT p. 579Furosemide FrusemideIt is a high ceiling loop diuretic which inhibits of Na-K-2cl- cotranspoer.The coicomedullary osmotic gradient is abolished and positive as well as negative free water clearance is blocked.K excretion is increased mainly due to high Na load reaching DT. 