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Diuretics
What is a diuretic?
A diuretic is a substance that causes the kidney to increase its production
of urine. Diuretics come in many form. Some everyday drinks, such as coffee,
tea or alcohol, can work as diuretics, as can several types of herbs. Prescription
diuretics are usually more powerful.
How do diuretics work?
All diuretics work directly or indirectly on the kidney cells. In general,
diuretics fall into two broad groups: those that increase kidney blood flow
and those that reduce the water reabsorption in the nephrons, tiny water filtering
units, of the kidney.
The first group includes effects other organs in the body, such as the heart,
and thus increases the blood flow in the kidney. Because there is more blood
passing through the kidney, more urine is produced. Caffeine, for example, falls
into this group: by speeding up the heart rate, it also increases blood flow
in the kidney.
The second group work in a number of different ways. Some change the osmotic
balance of the kidneys, causing more water to be lost. Others work by irritating
absorption through volatile oils, saponins or alkaloids.
Prescription diuretics act upon the kidney cells to increase the amount of
sodium and water that the body excretes.
Why are diuretics needed?
Diuretics are typically used in the following conditions:
· Congestive heart failure. The heart cannot pump normally, so excess water
builds up in the body.
· High blood pressure.
· Glaucoma. Increased fluid pressure in the eye threatens to cause blindness.
What side effects can diuretics cause?
Decreased potassium levels. Since diuretics increase the urine flow, they can
also increase the expulsion of important minerals, like potassium, from the
body. Since potassium, along with sodium and calcium, helps regulate your heart
rhythm and several other important body functions, low potassium levels can
cause weakness and irregular heart rate. Combat this problem with potassium
supplements, or with an increased intake of potassium-rich foods like leafy
vegetables, fruit juice, bananas, and decaffeinated coffee.
Reduced blood pressure. Diuretics can decrease the volume of fluid in the body,
which in turn can decrease blood pressure. Thus, may become light-headed or
even faint when you stand. Report such symptoms to your doctor right away.
Gout. Diuretics may raise uric acid levels in your blood. This increase puts
you at a higher risk of gout.
Aggravated diabetes. Diuretics can increase blood sugar, which is a problem
for diabetics.
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