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Diuretics are medications that promote the production of urine, and the elimination of water, salt, and electrolytes from the body. They are used to treat several different health conditions including heart disease, high blood pressure, and kidney disease.

Types of diuretics include:

  • Loop diuretics—Work in the loop of Henle in the kidney by inhibiting reabsorption of sodium and potassium. These are used in people with kidney problems.
  • Potassium-sparing diuretics—Work in the small tubules of the kidneys by inhibiting sodium reabsorption and retaining potassium in the body so it is not excreted in urine. These may be used in people who have or are at risk for hypokalemia.
  • Thiazide diuretics—Work in the small tubules of the kidney by inhibiting the reabsorption of sodium and potassium. These are one of the most commonly prescribed medications to treat high blood pressure.
  • Potassium-sparing and hydrochlorothiazide combination

What They Are Prescribed For

Diuretics may be prescribed to treat:

  • High blood pressure —sustained high force of blood flow against artery walls
  • Heart failure —inadequate circulation causes swelling resulting from fluid build-up
  • Lymphedema —inadequate lymph circulation causes swelling resulting from fluid build-up
  • Hypercalcemia—excess calcium levels in the blood
  • Hirsutism —excess hair growth in women that appears in places similar to men
  • Diabetes insipidus —water in the body is improperly removed from the circulatory system by the kidneys

Precautions While Taking a Diuretic

See Your Doctor Regularly

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.

Maintain a Healthy Potassium Level

Thiazide and 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 a potassium-sparing diuretic.

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

Do not make any dietary changes, even if you are on a special diet, without talking to your doctor first. Some diuretics do not cause potassium loss and may not require any dietary adjustment.

Do Not Take Diuretics During Pregnancy

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 medication when you are breastfeeding. Diuretics are not recommended for nursing mothers.

Manage Your Medications

Tell your doctor about all of the medications that you take. Some should not be taken with diuretics, while others may require a different dosage level. If you are taking any type of diuretic to control high blood pressure, check with your doctor before taking any over-the-counter medications, including those to treat colds, cough, and allergies.

Be Cautious With Conditions

The presence of other conditions may affect the use of diuretics. Tell your doctor if you have any other conditions, especially diabetes, kidney, liver, heart, and autoimmune disorders.

Eat a Healthy Diet and Exercise

Medications 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.

Do Not Ignore Dizziness

When you are taking a diuretic, you may have dizziness, or lightheadedness that can lead to 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.

Avoid the Sun

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. If you have skin problems because of the sun, 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 broad-spectrum sunscreen and sunblock lip balm with an SPF of at least 30.
  • Do not use a sunlamp or tanning bed or booth.

If you have a severe reaction from the sun, tell your doctor.

Talk to Your Doctor Before Stopping This Medication

It is essential to take your medication 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 medication as directed in order to keep your blood pressure under control. It may be possible to taper off the medication, particularly if you make lifestyle changes, such as diet and exercise, recommended by your doctor. If high blood pressure persists without treatment, it can lead to heart attacks, heart failure, blood vessel diseases, stroke, kidney failure, and/or blindness.

Dosing and Missed Doses

Take each dose at the same time each day. Since increase the amount of urine you produce, try to take your medication 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. Many of the effects of diuretics are similar, these side affects may occur with any one of these medications, although they may be more common with some more than with others. Side effects may be more prevalent in the elderly.

Side effects may depend on the type of diuretic used and include:

Diuretics are generally well tolerated by most people. If you are having problems with side effects talk to your doctor. You may be able to get your dose adjusted or try a different medication.


Family Doctor—American Academy of Family Physicians

US Pharmacopeial Convention

Canadian Resources

Canadian Pharmacists Association

Health Canada


Amiloride. EBSCO DynaMed website. Available at: Updated December 8, 2015. Accessed January 5, 2016.

Bumetanide. EBSCO DynaMed website. Available at: Updated December 8, 2015. Accessed January 5, 2016.

Chlorothiazide. EBSCO DynaMed website. Available at: Updated December 8, 2015. Accessed January 5, 2016.

Chronic kidney disease (CKD) in adults. EBSCO DynaMed website. Available at: Updated December 21, 2015. Accessed January 5, 2016.

Diuretics. US National Library of Medicine website. Available at: Updated January 30, 2015. Accessed January 5, 2016.

Hydrochlorothiazide. EBSCO DynaMed website. Available at: Updated December 8, 2015. Accessed January 5, 2016.

Hyperkalemia. EBSCO DynaMed website. Available at: Updated October 26, 2015. Accessed January 5, 2016.

Hypertension. EBSCO DynaMed website. Available at: Updated August 24, 2015. Accessed January 5, 2016.

Hypokalemia. EBSCO DynaMed website. Available at: Updated September 17, 2015. Accessed January 5, 2016.

Sunscreen FAQs. American Academy of Dermatology website. Available at: Accessed January 5, 2016.