Diuretics, sometimes called water pills, help rid your body of sodium and water. They work by making your kidneys excrete more sodium in urine. The sodium, in turn, takes water with it from your blood. That decreases the amount of fluid flowing through your blood vessels, which reduces pressure on the walls of your arteries.

There are three types of diuretics: thiazide, loop and potassium-sparing. Each works by affecting a different part of your kidneys, and each may have different uses, side effects and precautions. Which diuretic is best for you depends on your health and the condition being treated.

Examples of thiazide diuretics include:

• Hydrochlorothiazide
• Metolazone (Zaroxolyn)

Examples of loop diuretics include:

• Furosemide (Lasix)
• Bumetanide (Bumex)

Examples of potassium-sparing diuretics include:

• Spironolactone (Aldactone)
• Eplerenone (Inspra)

Different types of diuretics may also be combined into one pill.

A large group of medical experts known as the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends that most people should try thiazide diuretics as the first choice to treat high blood pressure and heart problems related to high blood pressure. In addition, doctors prescribe certain diuretics to prevent, treat or improve symptoms in a variety of conditions, such as:

• Congestive heart failure
• Edema
• Polycystic ovary syndrome
• Certain kidney disorders, such as kidney stones
• Diabetes insipidus
• Female hirsutism
• Osteoporosis

In general, potential side effects of diuretics include increased urination, weakness, dizziness, impotence, dehydration and, depending on the type of diuretic, potassium decrease or increase, or sodium decrease.