All diuretics promote the excretion of sodium. Depending upon the site and mode of action, some diuretics increase the excretion of potassium, chloride, calcium, bicarbonate, or magnesium. Some can reduce renal excretion of electrolyte-free water, calcium, potassium, or protons.
Consequently, electrolyte and acid-base disorders commonly accompany diuretic use. Except for the mildly natriuretic collecting duct agents, which are used mainly to limit potassium excretion, all diuretics can cause volume depletion with prerenal azotemia.
Loop agents and distal convoluted tubule agents, such as the thiazides, produce hypokalemia, hypochloremic, metabolic alkalosis that responds to potassium chloride replacement.
therefore, drinking plenty of water (mineral/alkaline) if possible is recommended when taking diuretics to prevent symptoms of metabolic acidosis.