Diuretic is any substance that increases the flow of urine and therefore the excretion of water.

Water diuresis (acquaresis) is the urinary excretion of sodium-free water

Natriuresis is the urinary loss of both water and sodium

Diuretics are drugs that promote the excretion of sodium and water by inhibiting the reabsorption of sodium in the renal tubules.

Diuretics are most commonly used in the treatment of hypertension and in conditions associated with volume overload such as heart failure and liver cirrhosis.

Different classes of diuretics have distinct pharmacokinetic and pharmacodynamic properties and varying mechanisms of action; therefore the indications for their use vary.

• Loop diuretics are typically the first choice for oedematous disorders (heart failure, nephrotic syndrome, liver cirrhosis), as well as for blood pressure and volume control in patients with advanced chronic kidney disease.

• Thiazides are considered first-line therapy for the treatment of patients with uncomplicated hypertension

• Potassium-sparing diuretics are most commonly used to correct potassium deficiency in patients with hypertension or to treaT conditions of excess aldosterone (aldosterone antagonists)

• Carbonic anhydrase inhibitors are mainly used to treat glaucoma

• osmotic diuretics are the first choice for cerebral edema.

• Diuretics can cause several adverse effects, in particular electrolyte and acid-base disturbances.

• The most serious side effects of the majority of diuretics include volume depletion and excessive changes in serum electrolyte levels (particularly of sodium and potassium), which increases the risk for cardiac arrhythmias.