Reviewed by: HU Medical Review Board | Last reviewed: June 2023

Diuretics, also known as water pills, are a type of drug used to treat some people with heart failure. Diuretics help the body release extra fluids and salt through urination. This helps reduce the swelling that often occurs in people with heart failure.1-6

Diuretics are also used to treat other conditions, including high blood pressure, kidney failure, cirrhosis, and glaucoma.1,2

How do diuretics work?

Diuretics regulate the salt and water balance of the body. They increase the elimination of these fluids, allowing the kidneys to get rid of extra water. Diuretics make you urinate more often, which is why they are often referred to as water pills.1-6

Reducing extra salt and water in the body helps with heart failure by:1-6

  • Lowering blood pressure
  • Reducing how hard your heart has to work
  • Reducing swelling and bloating


There are several types of diuretics available. Some drugs combine more than one type of diuretic. Your doctor will prescribe the right diuretic for you depending on your symptoms and medical condition.

Loop diuretics

Commonly prescribed loop diuretics include:3-6

  • Bumex® (bumetanide)
  • Edecrin® (ethacrynic acid)
  • Lasix®, Furoscix® (furosemide)
  • Soaanz® (torsemide)

Potassium-sparing diuretics

Commonly prescribed potassium-sparing diuretics include:3-6

  • Aldactone®, CaroSpir®  (spironolactone)
  • Dyrenium® (triamterene)
  • Inspra® (eplerenone)
  • Midamor® (amiloride)

Thiazide diuretics

Commonly prescribed thiazide diuretics include:3-6

  • Diuril® (chlorothiazide)
  • Esidrix®, Microzide® (hydrochlorothiazide)
  • Lozol® (indapamide)
  • Mykrox®, Zaroxolyn® (metolazone)
  • Thalitone® (chlorthalidone)

What are the possible side effects?

Side effects can vary depending on the specific drug you are taking. The most common side effects of diuretics include:3,5,6

  • Increased urination
  • Low potassium levels
  • Low sodium levels
  • Dizziness
  • Headaches
  • Dehydration
  • Muscle cramps

If you find that frequently going to the bathroom interferes with your sleep or certain activities, talk to your doctor about adjusting the medication schedule.3,5,6

These are not all the possible side effects of diuretics. Talk to your doctor about what to expect when taking a diuretic. You also should call your doctor if you have any changes that concern you when taking a diuretic.

Other things to know

Before starting treatment with a diuretic, tell your doctor if you:4,6

  • Take antidepressants, cyclosporine, lithium, or other medicines for high blood pressure
  • Have diabetes, gout, kidney problems, liver problems, lupus, or pancreatitis
  • Become dehydrated easily
  • Are pregnant or planning to become pregnant

Your doctor will regularly check your potassium levels and kidney function during treatment with a diuretic.5

Before beginning treatment for heart failure, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

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