What Is a Diuretic?

Medically Reviewed

Also known as “water pills,” these drugs rid the body of extra water and lower blood pressure.

Diuretics are a class of medications commonly known as "water pills."

They're prescribed to treat high blood pressure; swelling of the feet, ankles, and lower legs and fluid in the lungs caused by heart failure; fluid buildup in the abdomen caused by liver damage or certain cancers; and eye conditions such as glaucoma.

Other conditions that may be treated with diuretics include diabetes insipidus, polycystic ovarian syndrome (PCOS), kidney stones, male-pattern baldness in women, and osteoporosis.

There are several different classes of diuretics, each of which works differently in the kidneys to help rid the body of extra water and salt.

Examples of diuretics include:

Warnings and Precautions

Don't take diuretics if you have trouble urinating, or if you're allergic to the active or inactive ingredients found in the medication.

Ask your doctor if you should avoid or be cautious using diuretics if you:

Common Side Effects

It's not uncommon to experience any of the following while taking a diuretic:

  • Dizziness or headache
  • Thirstiness
  • Rash or itching
  • Higher blood glucose or cholesterol level
  • Changes in your sexual function or menstrual period
  • Muscle cramps (loop diuretics)
  • Ringing in the ears (loop diuretics)
  • Low sodium, potassium, and/or magnesium levels in the blood (loop diuretics)
  • High potassium levels in the blood (potassium-sparing diuretics)
  • Enlarged breasts in men (Aldactone and Inspra)

Drug Interactions

Many drugs can interact with diuretics, but double-check with your doctor or pharmacist to make sure you're not taking more than one diuretic at a time (unless your doctor has told you otherwise).

Don't take loop diuretics if you're taking Tikosyn (dofetilide).

Make sure your potassium is carefully monitored if you're using digoxin and a loop or thiazide diuretic.

Dosages of insulin and oral diabetes medications may need to be adjusted while using diuretics.

Ask your doctor about diuretics if you're taking the mood stabilizer Lithobid (lithium), or if you're taking any medication that may lead you to feel dehydrated.