In medicine, diuretics are used to treat heart failure, liver cirrhosis, hypertension, influenza, water poisoning, and certain kidney diseases.

Indapamide was specifically designed with this in mind, and has a larger therapeutic window for hypertension (without pronounced diuresis) than most other diuretics.

[citation needed] High-ceiling diuretics may cause a substantial diuresis – up to 20%[3] of the filtered load of NaCl (salt) and water.

[9] Osmotic diuretics (e. g., mannitol) are substances that increase osmolarity, but have limited tubular epithelial cell permeability.

They work primarily by expanding extracellular fluid and plasma volume, therefore increasing blood flow to the kidney, particularly the peritubular capillaries.

Further, the limited tubular epithelial cell permeability increases osmolality and thus water retention in the filtrate.

[10] It was previously believed that the primary mechanism of osmotic diuretics such as mannitol is that they are filtered in the glomerulus, but cannot be reabsorbed.

Thus their presence leads to an increase in the osmolarity of the filtrate and to maintain osmotic balance, water is retained in the urine.

However, in certain conditions, such as diabetes mellitus, the concentration of glucose in the blood (hyperglycemia) exceeds the maximum reabsorption capacity of the kidney.

Glucosuria causes a loss of hypotonic water and Na+, leading to a hypertonic state with signs of volume depletion, such as dry mucosa, hypotension, tachycardia, and decreased turgor of the skin.

[12] Caffeine when initially consumed in large quantities is both a diuretic and a natriuretic,[18] but this effect disappears with chronic consumption.