If you have high blood pressure or heart failure, your doctor may prescribe diuretics.

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Diuretics are medicines that aid the elimination of sodium (salt) and water from the body. The oral forms of these drugs are sometimes referred to as "water pills." Diuretics act by increasing the excretion by the kidneys of sodium in the urine. When the kidneys excrete sodium, they excrete water from the blood along with it. That decreases the amount of fluid flowing through the blood vessels, which reduces pressure on the walls of the arteries.

Diuretics are used to treat a number of conditions, including:

On the next page, we'll find out about the different kinds of diuretics.­