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Type of Medication | Medications and Their Commonly Used Brand Names | What They Are Prescribed For | How Diuretics Work | Precautions While Taking a Diuretic | Dosing and Missed Doses | Possible Side Effects

Type of Medication

Diuretic, often called "water pills"

Medications and Their Commonly Used Brand Names

ClassificationGeneric NameBrand Name
Loop DiureticsbumetanideBumex
ethacrynic acidEdecrin
Potassium-sparing DiureticsamilorideMidamor
Thiazide DiureticsbendroflumethiazideNaturetin
hydrochlorothiazideHydroDIURIL, Microzide (many other brands)
hydroflumethiazideDiucardin, Saluron
methyclothiazideAquatensen, Enduron
trichlormethiazideMetahydrin, Naqua
Potassium-sparing and Hydrochlorothiazide Combinationamiloride and hydrochlorothiazideModuretic
spironolactone and hydrochlorothiazideAldactazide
triamterene and hydrochlorothiazideDyazide, Maxzide

What They Are Prescribed For

Diuretics may be prescribed to treat:

Diuretics may also be used to treat:

How Diuretics Work

Diuretics act on the kidneys to increase the production of urine. Unlike other types, potassium-sparing diuretics do not cause your body to lose potassium.

Precautions While Taking a Diuretic

It is important that your doctor checks your progress at regular visits to allow for dosage adjustments and to manage any side effects. Before you have any type of surgery, including dental surgery, emergency treatment, or medical tests, make sure the doctor or dentist knows that you are taking a diuretic.

Thiazide diuretics and especially loop diuretics may cause an excessive loss of potassium from your body. To help prevent this, your doctor may recommend that you:

  • Choose foods and drinks that are high in potassium. Potassium is found in many foods, especially fruits and vegetables. Examples include dried figs, avocados, potatoes, bananas, oranges, and raisins.
  • Take a potassium supplement.
  • Take another medicine to help prevent the loss of potassium.

To prevent the loss of too much water and potassium, tell your doctor if you become sick, especially with severe or continuing vomiting or diarrhea.

It is essential to follow your doctor's instructions with regard to potassium and dietary changes. Extra potassium may not be needed. In some cases, too much potassium can be harmful. Potassium-sparing diuretics do not cause a loss of potassium from your body as some other diuretics do. Therefore, if you are taking this type of diuretic, it is not necessary for you to get extra potassium in your diet. Since salt substitutes and low-sodium milk may contain potassium, do not use them unless told to do so by your doctor.

If you are already on a special diet, as in the case of diabetes, it is especially important to talk to your doctor before making any dietary changes.

Diuretics are generally not useful for treating the normal swelling of hands and feet that can occur with pregnancy. Diuretics should not be taken during pregnancy unless recommended by your doctor. You also need to be cautious about taking medicine when you are breastfeeding. Diuretics are not recommended for nursing mothers.

  • Loop diuretics and thiazide diuretics: Dizziness, lightheadedness, or signs of excessive potassium loss are more likely to occur in elderly people. If you are an older adult, you are more prone to excessive dehydration and its complications.
  • Potassium-sparing diuretics: Symptoms of too much potassium are more likely to occur in the elderly.

Tell your doctor about all of the medicines that you take. Some should not be taken with diuretics, while others may require a different dosage level. Some common medicines that fall under these categories include:

  • Angiotensin-converting enzyme (ACE) inhibitors
  • Lithium
  • Certain antibiotics
  • Digoxin (Lanoxin)
  • Cholestyramine (Questran)
  • Colestipol (Colestid)
  • Potassium-containing medicines or supplements

If you are taking any type of diuretic to control high blood pressure, check with your doctor before taking these over-the-counter medicines to treat:

The presence of other conditions may affect the use of diuretics. Tell your doctor if you have any other conditions, especially:

Medicines are only part of the treatment for high blood pressure. Research has shown that you can help control your blood pressure by eating a low-sodium diet that is rich in fruits, vegetables, and low-fat dairy. Exercising regularly and maintaining a healthy weight are also essential lifestyle factors to manage high blood pressure.

When you are taking a diuretic, you may have dizziness, lightheadedness, or fainting. This may happen when you get up from a lying or sitting position. Getting up slowly may help. These symptoms are also more likely to occur if you drink alcohol, stand for long periods of time, exercise vigorously, or if the weather is hot. If the problem continues or worsens, tell your doctor.

Some diuretics may cause your skin to be more sensitive to sunlight. Exposure to sunlight, even for brief periods of time, may cause a rash, itching, redness, or sunburn. When taking these diuretics, follow these precautions:

  • Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m.
  • Wear protective clothing, including a hat and sunglasses.
  • Apply sunscreen and sunblock lip balm with an SPF of at least 15.
  • Do not use a sunlamp or tanning bed or booth.
  • If you have a severe reaction from the sun, tell your doctor.

It is essential to take your medicine even if you feel fine and do not have any symptoms, which is often the case with high blood pressure. You must continue to take the medicine as directed in order to keep your blood pressure under control. It may be possible to taper off the medicine, particularly if you make lifestyle changes (eg, diet and exercises) recommended by your doctor. If high blood pressure persists without treatment, it can lead to heart attacks, heart failure, blood vessel disease, stroke, kidney failure, and/or blindness.

Dosing and Missed Doses

Take each dose at the same time each day. Since diuretics work by increasing the amount of urine you produce, try to take your medicine early in the day so that your need to urinate will not disrupt your sleep.

  • If you take a single dose, take it after breakfast.
  • If you take more than one dose, take the last dose no later than 6:00 p.m., unless otherwise directed by your doctor.

If the diuretic upsets your stomach, it may be taken with food or drink. If stomach upset continues or gets worse, or if you suddenly get severe diarrhea, tell your doctor.

If you miss a dose, take it as soon as possible. But if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Possible Side Effects

The side effects listed here are most commonly encountered with at least one type of diuretic drug, not necessarily all of them. But since many of the effects of diuretics are similar, these side affects may occur with any one of these medicines, although they may be more common with some more than with others. If you have any side effects, tell your doctor.

  • Extreme tiredness
  • Lightheadedness, dizziness, or loss of consciousness
  • Decreased urination
  • Dryness of mouth and extreme thirst
  • Dryness of mouth
  • Increased thirst
  • Irregular heartbeat
  • Mood or mental changes
  • Muscle cramps or pain
  • Nausea or vomiting
  • Unusual tiredness or weakness
  • Weak pulse
  • Confusion
  • Irregular heartbeat
  • Nervousness
  • Numbness or tingling in hands, feet, or lips
  • Shortness of breath or difficulty breathing
  • Unusual tiredness or weakness
  • Weakness or heaviness of legs
  • Confusion
  • Convulsions
  • Decreased mental activity
  • Irritability
  • Muscle cramps
  • Unusual tiredness or weakness

Check with your doctor if any of the following side effects occur frequently and/or become bothersome:

  • Loss of appetite
  • Nausea and vomiting
  • Stomach cramps and diarrhea
  • Constipation
  • Sunburn
  • Impotence

There are also many less common side effects that have been reported with diuretic use. If you develop any new symptoms after starting this medicine, talk to your doctor.


American Academy of Family Physicians


USP Drug Information



Canadian Pharmacists Association



Amiloride. EBSCO Health Library website. Available at: http://www.ebscohost.com/healthLibrary/. Updated December 2009. Accessed February 25, 2010.

Amiloride and hydrochlorothiazide. EBSCO Health Library website. Available at: http://www.ebscohost.com/healthLibrary/. Updated December 2009. Accessed February 25, 2010.

Bumetanide. EBSCO Health Library website. Available at: http://www.ebscohost.com/healthLibrary/. Updated December 2009. Accessed February 25, 2010.

Chlorothiazide. EBSCO Health Library website. Available at: http://www.ebscohost.com/healthLibrary/. Updated December 2009. Accessed February 25, 2010.

Chronic kidney disease. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated February 2010. Accessed February 26, 2010.

High blood pressure (hypertension). Mayo Clinic website. Available at: http://www.jrank.org/health/pages/2256/loop-diuretics.html. Updated June 23, 2009. Accessed February 25, 2010.

Loop diuretics. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated April 26, 2011. Accessed May 30, 2012.

Potassium-sparing diurectics. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated January 21, 2011. Accessed May 30, 2012.

Thiazide-type diuretics. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated January 21, 2011. Accessed May 30, 2012.

Last reviewed May 2012 by Brian Randall, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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