Heart Disease and Diuretics

Medically Reviewed by James Beckerman, MD, FACC on March 08, 2021

Sometimes, diuretics -- also called water pills -- are used to treat heart disease. They help your body get rid of unneeded water and salt through urine. That makes it easier for your heart to pump and to control blood pressure.

Examples of diuretics include:

Diuretics are categorized as:

Thiazide-like: These get rid of a moderate amount of water. They can be used for a long time.

Loop: They’re more powerful and are very useful in emergencies.

Potassium-sparing: They help you keep potassium as you’re getting rid of water and salt. You’ll sometimes take these with one of the other two types mentioned above.

Who Should Take Them?

Your doctor may recommend a diuretic if you have.

Edema: Diuretics lessen swelling that usually occurs in the legs.

High blood pressure: Thiazide diuretics lower blood pressure. That lowers your chance of a stroke or heart attack.

Heart failure: Diuretics ease swelling and congestion in the lungs. Normally, you’ll get a loop diuretic for heart failure.

Kidney problems: You’ll keep less water.

Liver problems: If you have cirrhosis, a diuretic will ease the fluid buildup you’ll get with it.

Glaucoma: They’ll reduce the pressure in your eye.

How Should I Take Them?

Before you’re prescribed a diuretic, tell your doctor if you have diabetes, kidney disease, liver disease, or gout.

Follow the directions on the label. If you’re taking one dose a day, take it in the morning with your breakfast or right after. If you are taking more than one dose a day, take the last one no later than 4 p.m.

The number of doses you take each day, the time allowed between doses, and how long you need to take a diuretic will depend on the type prescribed, as well as your condition.

Weigh yourself at the same time every day (on the same scale) and write down your weight. Call your doctor if you gain 3 pounds in one day or 5 pounds in one week.

While you’re taking these, have your blood pressure and kidney strength tested regularly. Diuretics can change your blood potassium and magnesium levels.

Keep all your doctor and lab appointments so your response to this medicine can be tracked.

What Are the Side Effects?

They can include:

Frequent peeing: This may last for up to 4 hours after each dose. If you are taking two doses each day, take the second dose no later than late afternoon so you can sleep through the night without waking up to urinate.

Extreme tiredness or weakness: These should ease as your body gets used to the medicine. Call your doctor if these symptoms hang around. That could mean your dose needs to be adjusted.

Muscle cramps or weakness: Make sure you’re taking your potassium supplement correctly, if you’ve been prescribed one. Contact your doctor or nurse if these symptoms continue.

Thirst: Try sucking on sugarless hard candy. Contact your doctor or nurse if you have extreme thirst. It could be a sign of dehydration.

Dizziness, lightheadedness: Try getting up more slowly from a lying or sitting position.

Blurred vision, confusion, headache, increased sweating, restlessness: If any of these are constant or severe, call your doctor.

Dehydration: Signs include:


If you have any of these, don't assume you need more fluids -- call your doctor or nurse.

  • Fever, sore throat, cough, ringing in the ears, unusual bleeding or bruising, rapid and excessive weight loss: Contact your doctor right away.
  • Skin rash: Stop taking the medication and contact your doctor right away.
  • Loss of appetite, nausea, vomiting, or muscle cramps: Be sure you’re taking your potassium supplement correctly, if you were prescribed one. Contact your doctor or nurse if these symptoms persist.

Contact your doctor or nurse if you have any other symptoms that concern you.

What Foods or Drugs Interact With Them?

To avoid a potential problem, tell your doctor and pharmacist all the medicines you are taking, including:

Diuretics are often prescribed with other drugs. If you have more side effects when you take them together, contact your doctor. You may need to change the times you take each one.

Before a diuretic is prescribed, tell your doctor if you are taking:

Some diuretics may require you to avoid or eat certain foods. Follow your doctor's advice, which may include:

  • A low-salt diet
  • A potassium supplement or high-potassium foods such as bananas and orange juice.

As always, talk with your doctor.

Can Pregnant Women Take Them?

Check with your doctor if you are pregnant or planning to become pregnant while taking a diuretic.

Can Breastfeeding Women Take Diuretics?

Most diuretics are fine, with some precautions. Talk with your doctor.

Can Children Take Them?

Yes. The side effects are similar to those in adults. Children will take smaller doses. Talk with your doctor.

WebMD Medical Reference


SOURCES: "Diuretics in Heart Failure." "Diuretics."

Texas Heart Institute: "Diuretics."



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