Diuretics




Types of diuretic



Diuretics (also called water tablets or water pills) increase your urine output, salt excretion in the urine is also increased. They work mainly by reducing resistance in the blood vessels.

There are three types of diuretics: thiazide, loop and potassium sparing:


Thiazide diuretics

These are effective and widely used. They are good for use in the elderly. They are also used in patients with diabetes . They are often used in combination with other antihypertensive drugs such as beta blockers, ACE inhibitors and calcium channel blockers.

This class of water tablet increases the loss of potassium in the urine and therefore blood levels may need to be checked at intervals. If your blood levels are low your doctor will need to prescribe you potassium supplements to keep you topped up.

Thiazide diuretics can occasionally cause a modest increase in cholesterol levels, though this is unlikely to be severe enough to warrant changing drugs. Rarely also they can worsen or precipitate gout and type 2 diabetes. Diuretics have been occasionally associated with sexual dysfunction in men.

If you are taking these drugs, it is a good idea to keep to a low salt diet as salt lessens the effect of the drug.

Examples: Hydrochlorothiazide; Indapamide


Loop Diuretics

These are prescribed less often and are used for patients who also have heart failure. They are less convenient to take as they need to be taken twice daily.

They also cause potassium loss and may need to be prescribed along with potassium supplements.

Example: Frusemide.


Potassium sparing diuretics

These, as the name suggests do not cause loss of potassium in the urine, they help conserve potassium and can be used with thiazide diuretics. They are much more commonly used in the treatment of heart failure.Example: Spironolactone. A noted side effect is enlargement and tenderness of breast tissue in men.


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This page was last modified on : May 16, 2011.