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Hypertension/High Blood Pressure Health Center

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High Blood Pressure and Diuretics (Water Pills)

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For high blood pressure, diuretics, commonly known as "water pills," help your body get rid of unneeded water and salt through the urine. Getting rid of excess salt and fluid helps lower blood pressure and can make it easier for your heart to pump. Diuretics may be used to treat a number of heart-related conditions, including high blood pressure, heart failure, kidney and liver problems, and glaucoma.

Thiazide diuretics, such as Esidrix or Zaroxolyn, can be used to lower blood pressure, or to treat edema in heart failure.

Loop diuretics (Lasix, Bumex) are often used when people have congestive heart failure symptoms and are especially useful in emergencies. However, they do not significantly lower blood pressure.

Potassium-sparing diuretics (like Aldactone, Dyrenium) help your body retain potassium and are used more often in congestive heart failure patients. They are often prescribed in conjunction with the other two types of diuretics, but also do not significantly lower blood pressure.

What Are the Side Effects of Diuretics?

Like any drug, diuretics come with potential side effects. They can include:

  • Frequent urination. This may last for several hours after a dose.
  • Arrhythmia(abnormal heart rhythm)
  • Electrolyte abnormalities -- Blood test monitoring of blood chemistries or electrolytes, such as potassium, sodium, or kidney function, is important before and during drug use.
  • Extreme tiredness or weakness. These effects should decrease as your body adjusts to the medication. Call your doctor if these symptoms persist.
  • Muscle cramps or weakness. If you take potassium supplements, be sure that you are taking your potassium supplement correctly, if prescribed. Contact your doctor if these symptoms persist.
  • Dizziness, lightheadedness. Try rising more slowly when getting up from a lying or sitting position.
  • Blurred vision, confusion, headache, increased perspiration (sweating), and restlessness. If these effects are persistent or severe, contact your doctor.
  • Dehydration. Signs include dizziness, extreme thirst, excessive dryness of the mouth, decreased urine output, dark-colored urine, or constipation. If these symptoms occur, don't assume you need more fluids, call your doctor.
  • 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 that you are taking your potassium supplement correctly, if prescribed.

Rarely, potassium-sparing diuretics like Aldactone can cause breast enlargement or tenderness in men and in women it can cause deepening of the voice, decreased hair growth, and irregular menstrual cycles.

In addition, most diuretics are sulfa drugs. If you are allergic to sulfa drugs, tell your doctor.

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

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