Mayo Clinic Health Library

Diuretics

Updated: 10-19-2019

Diuretics, sometimes called water pills, help rid your body of salt (sodium) and water. Most of them help your kidneys release more sodium into your urine. The sodium takes with it water from your blood, decreasing the amount of fluid flowing through your veins and arteries. This reduces blood pressure.

Examples of diuretics

There are three types of diuretics:

  • Thiazide
  • Loop
  • Potassium sparing

Each type affects a different part of your kidneys. Some pills combine more than one type of diuretic or combine a diuretic with another blood pressure medication.

Which diuretic is best for you depends on your health and the condition being treated.

Examples of oral thiazide diuretics include:

  • Chlorothiazide (Diuril)
  • Chlorthalidone
  • Hydrochlorothiazide (Microzide)
  • Indapamide
  • Metolazone

Examples of loop diuretics include:

  • Bumetanide (Bumex)
  • Ethacrynic acid (Edecrin)
  • Furosemide (Lasix)
  • Torsemide (Demadex)

Examples of potassium-sparing diuretics include:

  • Amiloride
  • Eplerenone (Inspra)
  • Spironolactone (Aldactone, Carospir)
  • Triamterene (Dyrenium)

When diuretics are used

Thiazide diuretics are recommended as one of the first drug treatments for high blood pressure.

If diuretics aren't enough to lower your blood pressure, your doctor might add other blood pressure medications to your treatment plan.

Diuretics are also used to prevent, treat or improve symptoms in people who have:

  • Heart failure
  • Liver failure
  • Tissue swelling (edema)
  • Certain kidney disorders, such as kidney stones

Side effects

Diuretics are generally safe. Side effects include increased urination and sodium loss.

Diuretics can also affect blood potassium levels. If you take a thiazide diuretic, your potassium level can drop too low (hypokalemia), which can cause life-threatening problems with your heartbeat. If you're on a potassium-sparing diuretic, you can have too much potassium in your blood.

Other possible side effects of diuretics include:

  • Dizziness
  • Headaches
  • Dehydration
  • Muscle cramps
  • Joint disorders (gout)
  • Impotence