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Diuretics Types and Side Effects

written by Tessa Chatham Registered Nurse Written by Tessa Chatham Registered Nurse
Tessa Chatham Registered Nurse

Tessa Chatham Registered Nurse

Tessa is a MSN prepared Registered Nurse with 10 years of critical care experience in healthcare. When not practicing clinical nursing, she enjoys academic writing and is passionate about helping those affected by medical aliments live healthy lives.

Read more posts by this author.
reviewed by Ken Cosby M.D. Reviewed by Ken Cosby M.D.
Ken Cosby M.D.

Ken Cosby M.D.

Dr. Ken Cosby received his medical degree from Howard University College of Medicine (Washington, DC) and completed his research post-doc work at Johns Hopkins University School of Medicine and the National Institutes of Health including the National Heart Lung Blood Institute and the National Cancer Institute.

July 9, 2021 Read Time - 5 minutes

What Are Diuretics?

Diuretics, or water pills, are types of medications used to treat certain medical conditions. 

Diuretics are available as over-the-counter and prescription medications, although they are usually used for different purposes.

Over-the-counter diuretics are typically marketed as weight loss supplements. The most common use for prescription diuretics is for the treatment of hypertension and heart failure. 

Prescription diuretics are used to treat:

  • High blood pressure (hypertension)
  • Kidney disease 
  • Heart disease
  • Liver disease
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How Do Diuretics Work?

Prescription diuretics work by acting on different parts of your kidneys to excrete sodium and water. This results in more urine flow. 

Some diuretics affect how much potassium leaves your body through the urine. These types of diuretics need close monitoring because too high or too low levels of potassium can be dangerous. 

Types of Diuretics:

Three types of prescription diuretics increase water excretion from your body, although each class does so in a distinctly different way.

The three main types of diuretics include:

  • Loop
  • Thiazide
  • Potassium-sparing

Loop Diuretics:

Loop diuretics work by inhibiting sodium reabsorption on specific kidney cells called the loop of Henle, hence the name, “loop” diuretic. 

Examples of loop diuretics include:

  • Bumetanide (Bumex)
  • Ethacrynic acid (Edecrin)
  • Furosemide (Lasix)
  • Torsemide (Demadex)

Thiazide Diuretics:

Thiazide diuretics work by acting directly on the kidneys to promote diuresis (urine flow) by inhibiting the sodium/chloride cotransporter located in the distal convoluted tubule of the functional part of the kidney (nephron). 

Examples of oral thiazide diuretics include:

  • Chlorothiazide (Diuril)
  • Chlorthalidone
  • Hydrochlorothiazide (Microzide)
  • Indapamide
  • Metolazone

Both loop and thiazide diuretics can lower potassium levels in the blood as they increase sodium delivery, increasing potassium loss. 

Low potassium levels (hypokalemia) can cause heart arrhythmias and even cardiac arrest. Often, potassium pills are given concurrently with loop diuretic therapy to keep potassium levels safe. 

If potassium pills are not prescribed, doctors may suggest you consume foods with high levels of potassium, such as:

  • Bananas
  • Oranges
  • Cooked spinach
  • Cooked broccoli
  • Mushrooms
  • Cucumbers
  • Peas

Potassium-sparing Diuretics:

Potassium-sparing diuretics work by making the kidneys excrete more fluid (urine) without interfering with the sodium-potassium exchange in the kidney cells, thereby reducing or “sparing”  potassium. Potassium-sparing diuretics do not drastically reduce potassium levels in the blood and are used if loop or thiazide diuretics are not tolerated. 

Examples of common diuretics that are potassium-sparing include:

  • Amiloride
  • Eplerenone (Inspra)
  • Spironolactone (Aldactone, Carospir)
  • Triamterene (Dyrenium)

These medications are available in tablet form. Sometimes, diuretic tablets may be given intravenously in the hospital setting under close supervision. Home doses of diuretic pills are prescribed to take once or twice a day. 

Side Effects of Diuretics

Diuretics prescribed by a medical doctor should be taken only as directed. 

Some side effects of taking diuretics include:

  • Increased urination (expected)
  • Dizziness
  • Headaches
  • Dehydration
  • Muscle cramps
  • Joint disorders (gout)
  • Impotence

If you are prescribed a diuretic, you will most likely be asked to reduce the amount of salt you consume in your daily diet. Consuming salt will increase fluid in your body because water binds to salt. This results in more fluid accumulation and swelling. Swelling is most commonly seen in the feet, ankles, and legs. 

Food items high in salt that should be avoided include:

  • Smoked, cured, salted, or canned meat (ex: bacon, cold cuts, ham, frankfurters, sausage, sardines, caviar, and anchovies)
  • Frozen breaded meats and dinners (pizza, burritos)
  • Canned entrees, such as ravioli, spam, and chili
  • Salted nuts
  • Canned beans with salt
  • Breakfast cereals
  • Tomato sauce
  • Soy sauce and Asian stir fry sauces
  • Vegetable or meat stocks
  • Canned vegetables and legumes
  • Pasta sauce
  • Chips
  • Processed foods
  • Fast food 

When you are prescribed diuretics, your doctor may also suggest restricting the amount of fluid you drink daily. Consuming too much water or other liquids will also negate the work of diuretics. Many people will be put on a “fluid restriction” in conjunction with a diuretic prescription. 

Discuss salt and fluid restriction requirements with your doctor. Sometimes these restrictions can be more lenient depending on your condition and other factors within your treatment plan.

Who Should Not Take Diuretics?

Because diuretics can affect potassium levels, people with severe kidney problems or Addison’s disease should not take diuretics. 

Diuretics are contraindicated in patients with known drug hypersensitivity and those with electrolyte imbalances.

Can You Buy Diuretics Over the Counter

Some over-the-counter diuretics (OTC) are available for temporary weight loss and treating minor swelling, bloating, and water retention. 

You can buy diuretics over the counter, but they will not be prescription-grade. 

OTC diuretics should not be used as substitutes for prescribed diuretics.

Some common ingredients used for over-the-counter diuretic medications include:

  • Caffeine 
  • Dandelion Extract
  • Horsetail
  • Parsley
  • Hibiscus
  • Caraway
  • Green and Black Tea
  • Nigella Sativa

Some over-the-counter diuretics are used to treat bloating related to menstrual cycles. These are often paired with Non-steroidal anti-inflammatory drugs (NSAIDs) to reduce pain as well as swelling and bloating. 

Always use over-the-counter diuretics with caution as these types of medications can cause kidney damage if misused. If you have concerns about water retention or weight gain, talk with your doctor about treatment options, even before trying over-the-counter ones. Sometimes, over-the-counter medications are not suitable to mix with current prescription medications. 

  • Book on our free mobile app or website.

    Our doctors operate in all 50 states and same day appointments are available every 15 minutes.

  • See a doctor, get treatment and a prescription at your local pharmacy.

  • Use your health insurance just like you normally would to see your doctor.


Get Diuretics Online

Diuretics prescriptions are available online after you speak with a medical doctor. Loop, thiazides, and potassium-sparing diuretics are available through prescription. If you have symptoms of hypertension, heart failure, swelling, or water retention, prescription diuretics may be a treatment option for you. Diuretics work on your kidneys to secrete more water via urine flow and are used to treat hypertension and other medical conditions.

Talk with a PlushCare doctor today to get evaluated for possible treatment options. If needed, your doctor can prescribe diuretic medications to your local pharmacy the same day. If you are already diagnosed with conditions and take diuretics, talk with your provider about treatment options. 

To book an appointment with an online doctor with PlushCare, click here

Read More About Diuretics


PlushCare is dedicated to providing you with accurate and trustworthy health information.

Ellison D. H. (2019). Clinical Pharmacology in Diuretic Use. Clinical journal of the American Society of Nephrology: CJASN, 14(8), 1248–1257. Accessed on May 21, 2021 from

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