Diuretics, sometimes called water pills, help rid your body of salt (sodium) and water. Most work by making your kidneys release more sodium into your urine. The sodium then takes water with it from your blood. That decreases the amount of fluid flowing through your blood vessels, which reduces pressure on your vessel walls.
There are three types of diuretics: thiazide, loop and potassium-sparing. Each type affects a different part of your kidneys and may have different uses, side effects and precautions. Which diuretic is best for you depends on your health and the condition being treated.
Examples of thiazide diuretics include:
- Chlorothiazide (Diuril)
- Hydrochlorothiazide (Microzide)
Examples of loop diuretics include:
- Bumetanide (Bumex)
- Ethacrynic acid (Edecrin)
- Furosemide (Lasix)
- Torsemide (Demadex)
Examples of potassium-sparing diuretics include:
- Eplerenone (Inspra)
- Spironolactone (Aldactone)
- Triamterene (Dyrenium)
Some pills combine more than one type of diuretic or combine a diuretic with another blood pressure medication.
The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends that most people try thiazide diuretics first to treat high blood pressure and heart problems related to high blood pressure.
If diuretics aren't enough to lower your blood pressure, your doctor might recommend adding medications such as calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers or beta blockers to your blood pressure treatment.
In addition, doctors prescribe certain diuretics to prevent, treat or improve symptoms in a variety of conditions, such as:
- Heart failure
- Liver failure
- Tissue swelling (edema)
- Certain kidney disorders, such as kidney stones
Diuretics are generally safe, but they do have some side effects, such as increased urination and mineral loss.
Diuretics can also affect blood potassium levels. You can develop too much potassium (hyperkalemia) if you take a potassium-sparing diuretic or too little potassium (hypokalemia) if you take a thiazide diuretic.
Other possible side effects of diuretics include:
- Low sodium in your blood (hyponatremia)
- Muscle cramps
- Joint disorders (gout)