<prompt> The primary site of action of triameterene and spironolactone is the -Proximal tubuleDistal tubuleAscending Loop of HenleDescending Loop of Henle  <response>: Ans. is b i.e., Distal tubule o Potassium sparing diuretics Sprionolactone and triameterene act on late distal tubule and collecting duct. 