Virtually all cases of severe diuretic-induced hyponatremi have been due to a thiazide-type diuretic In contrast, loop diuretics are implicated much less commonly This observation is in the medullary thick ascending limb is normally the primary step in the generation of the hypertonicity in the medullary interstitium, and loop diuretics mainly impair urinary concentration and limit water retention and development of hyponatremia