Indomethacin can antagonize the diuretic action of loop diuretics by:: (A) Preventing prostaglandin mediated intrarenal-hemodynamic actions, (B) Blocking the action in ascending limb of loop of Henle, (C) Enhancing salt and water reabsorption in distal tubules, (D) Increasing aldosterone secretion
Answer is A. Loop diuretics release PGs that induce intrarenal hemodynamic changes which secondarily affect salt output. Indomethacin and other NSAIDs inhibit the formation of PG. Therefore, NSAIDs blunt the action of loop diuretics.