Published by TDP on July 1, 2017 Diuretics promote the excretion of water and electrolytes by the kidneys. They are used in the treatment of heart failure or in hepatic, renal, or pulmonary disease when salt and water retention has resulted in oedema or ascites. Diuretics are also used, either alone, or in association with other agents, in the treatment of hypertension. The principal groups of diuretics are thiazides, 'Loop' or 'high - ceiling' diuretics، potassium sparing diuretics, osmotic diuretics, Mercurial diuretics and carbonic anhydrase inhibitors.