What Are Diuretics?

Diuretics are a common medication used to treat high blood pressure. They are relatively inexpensive and are widely available. In addition to high blood pressure, diuretics are often used to treat other illnesses, including:

  • Heart Failure
  • Edema
  • Some types of poisoning

While the general action of diuretics is to increase excretion of salt and water, many diuretics can lower blood pressure at lower doses than those needed to cause diuresis (excretion).

How Diuretics Work:

The term "diuretic" is very broad, and refers generally to any substance that cause the kidneys to get rid of extra water and salt. There are many kinds of diuretics, and each diuretic works on different parts of the kidneys.

Some of the common classes of diuretics include:

Each class of diuretic has a different specific mechanism of action, but all typically share the ultimate outcome of changing the way the kidneys handle salt, water, and other substances.

Common Diuretic Names:

Many different diuretics are available. Some commonly prescribed diuretics include:

  • Furosemide
  • Hydrochlorothiazide, also known as HCTZ
  • Spironolactone
  • Metolazone

Many other diuretics are available, both within the United States and around the world. However, the vast majority of prescriptions in the U.S. are for the drugs listed above.

Other types of diuretics are used in special circumstances or controlled hospital settings.

Diuretic Side Effects:

Because there are many different classes, or types, of diuretics, there are many possible side effects associated with their use. In general, side effects can include things such as:

  • Excessive urination
  • Electrolyte imbalance
  • Increased blood sugar
  • Dizziness
  • Dry mouth
  • Headache
  • Increased thirst
Because some diuretics can raise blood sugar, careful monitoring is important if you have diabetes.

This list of side effects is not exhaustive. If you experience any abnormal reactions to taking medication, you should always consult with your physician.


Only you and your doctor can decide on a proper medication for treatment of high blood pressure. Be sure to notify your doctor if you are pregant or breastfeeding, and to supply the names of any other medicines and/or suppliments you are taking. Remember to include over-the-counter medicines like aspirin or Advil and herbal/natural suppliments.

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