Alternative names: Diuretic, Water Pill, Water Pills.
A diuretic is a drug or other substance that increases a person's urine and salt excretion.
There are three types of diuretic: thiazide, loop and potassium-sparing. Each affects a different part of the kidneys, and each has different uses and side-effects. Which diuretic is best depends on a person's health and on the condition being treated.
Diuretics are often abused by sufferers of eating disorders, especially bulimics, in attempts at weight loss.
Diuretics help rid the body of water and salt by making the kidneys excrete more sodium into the urine. The sodium takes water with it, increasing urine output and decreasing the amount of fluid flowing through the blood vessels, which in turn reduces pressure on the walls of the arteries.
The blood-pressure-lowering actions of some diuretics (thiazides and loop diuretics in particular) are unrelated to their diuretic effect: the reduction in blood pressure is not due to decreased blood volume, but occurs through other mechanisms and at lower doses.
Getting rid of excess salt and water helps lower blood pressure and makes it easier for the heart to pump blood. For this reason, diuretics are used in the treatment of several heart-related conditions.
Some diuretics, such as acetazolamide, help to make the urine more alkaline and help to increasing excretion of substances such as aspirin in cases of overdose or poisoning.
While taking diuretics, doctors usually recommend having blood pressure and kidney function tested regularly. A low-salt diet is often recommended, as well as potassium supplements or foods high in potassium.
Alcohol and sleep medications may increase side-effects and should be avoided.
It is not advisable to take diuretics while pregnant or breast-feeding.
Potassium-sparing diuretics such as Aldactone or Dyrenium help the body to retain potassium and are often used in congestive heart failure patients, often along with the other two types of diuretics. They do not significantly lower blood pressure.
Loop diuretics such as Lasix or Bumex are often used to counter congestive heart failure symptoms and are especially useful in emergencies. They do not, however, significantly lower blood pressure. Thiazide diuretics, such as Esidrix or Zaroxolyn, can be used to treat edema in heart failure.
Some diuretics are useful against osteoporosis: Thiazides lower urinary calcium excretion, resulting in a positive calcium balance and increased bone mineral density and a reduction in fracture rates due to osteoporosis. For reasons not fully understood, thiazides also stimulate bone mineral formation, which helps to slow the course of osteoporosis.