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Diuretics are used to treat high blood pressure and used to treat heart failure. Diuretics, commonly known as water pills, help your body get rid of unneeded water and salt through the urine. Getting rid of excess fluid makes it easier for your heart to pump and helps control blood pressure.

Who should take diuretics?

If you have any of the following conditions, your doctor may recommend you take a diuretic.

  • Oedema. Diuretics decrease swelling (oedema) that usually occurs in the legs.
  • High blood pressure. Diuretics lower blood pressure, which substantially reduces the risk of stroke and heart attack.
  • Heart failure. Diuretics reduce the swelling (oedema) and water build-up in the lungs (congestion) caused by heart failure.
  • Kidney problems. Diuretics reduce water retention.
  • Liver problems. Diuretics reduce the amount of fluid build-up associated with cirrhosis (disease of the liver).
  • Glaucoma. Diuretics reduce the pressure in the eye associated with this disease.

Loop diuretics are the diuretics most likely to be prescribed for heart failure. Furosemide, bumetanide, and torasemide are the loop diuretics used for the management of oedema from congestive heart failure.

Thiazide diuretics help to manage high blood pressure and to manage oedema due to congestive heart failure. They include bendroflumethiazide, indapamide and metolazone.

Potassium-sparing diuretics are not generally recommended in the management of heart failure.

Diuretic warnings

Diuretics are not suitable during pregnancy or for people with gout. Make sure a doctor knows about existing medical conditions and any medicines already prescribed, or supplements, or over the counter treatments being taken.

Take diuretics as advised by the doctor and seek medical advice if a dose is missed or an extra dose taken by mistake.

Diuretics can raise potassium and blood sugar levels, so a doctor will arrange regular blood and urine tests.

Side effects of diuretics include:

  • Erectile dysfunction or impotence
  • Frequent urination. This may last for up to four hours after each dose. If you are taking two diuretic doses each day, take the second dose no later than late afternoon so you can sleep through the night.
  • Extreme tiredness or weakness. These effects should decrease as your body adjusts to the medication. Seek medical advice if these symptoms persist, since these symptoms could mean your medication dose needs to be adjusted.
  • Muscle cramps or weakness. Make sure that you are taking your potassium supplement correctly, if prescribed. Seek medical advice if these symptoms persist.
  • Thirst. Try sucking on sugar-free sweet. Seek medical advice if you have extreme thirst, which could be a sign of dehydration or of diabetes.
  • Dizziness, lightheadedness. Try rising more slowly when getting up from a lying or sitting position.
  • Blurred vision, confusion, headache, increased perspiration ( sweating), restlessness. If these effects are persistent or severe, seek medical advice.
  • Dehydration. Signs include dizziness, extreme thirst, excessive dryness of the mouth, decreased urine output, dark-coloured urine, or constipation. If these symptoms occur, don't assume you need more fluids, seek medical advice.
  • Fever, sore throat, cough, ringing in the ears, unusual bleeding or bruising, rapid and excessive weight loss. Seek urgent medical advice.
  • Skin rash. Seek urgent medical advice.
  • Loss of appetite, nausea, vomiting or muscle cramps. Be sure that you are taking your potassium supplement correctly, if prescribed. Seek medical advice if the symptoms continue.

Seek medical advice if you have any other symptoms that cause concern.

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WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on October 22, 2014

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