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Water Pills: Things to Know About Diuretics for Hypertension

Water Pills: Things to Know About Diuretics for Hypertension

Diuretics or water pills are medicines that promote the elimination of water and sodium (salt) through increased urine production. Many hypertensive people take diuretics because it helps lower blood pressure. If you need more information about water pills, you might find this guide helpful.

Types of Diuretics and How They Work

The first thing you have to understand about water pills is their mechanism of action or how they help lower your blood pressure.

Mechanisms of action depend on the type of diuretic. Your doctor will choose the best type of diuretic for you, depending on your condition and overall health.


Thiazide water pills work by reducing sodium reabsorption in the kidney, thereby increasing the sodium in the urine1. Note that water from the blood “follows” sodium. So, both sodium and water are eliminated through urination.

With a decreased amount of fluid flowing in the blood vessels, it’ll be easier for your heart to pump. This then helps reduce blood pressure. It is also worth mentioning that Thiazide lowers pressure by “widening” the blood vessels2.

Examples: Chlorothiazide, Hydrochlorothiazide, Metolazone


Loop diuretics act on the part of kidneys called the “Loop of Henle.”

Their mechanism of action is similar to Thiazide water pills. A key difference is that loop diuretics do not widen blood vessels.

Examples: Furosemide, Bumetanide, Torsemide


In the process of eliminating water and salt, Loop and Thiazide diuretics also cause the body to lose potassium.

Potassium-sparing water pills “spares” potassium. Doctors often prescribe it to patients who are prone to hypokalemia (low potassium levels)3.

Examples: Amiloride, Spironolactone, Eplerenone

Expected Effects of Using Diuretics

Besides lowering the blood pressure, water pills can also help:

  • Improve shortness of breath
  • Reduce bloating or swelling
  • Prolong life after heart failure
  • Reduce the time patients spend in the hospital

Guidelines When Taking Water Pills

If you have hypertension, don’t be surprised if the doctor prescribes you diuretics right away.

You see, diuretics are recommended as one of the first drug treatments for hypertension. In fact, a study recommends water pills to be the “drug of choice” for stage 1 hypertension4.

Below are some guidelines when taking diuretics:

1. Take water pills at least 6 hours before bedtime.

Strictly follow your doctor’s orders about taking diuretics.

In most cases, they will ask you to take your medicine at least 6 hours before bedtime. This can reduce sleep disruption from needing to pee in the middle of the night.

2. Do not increase your salt intake.

Once you understand that water pills get rid of salt in the body, you might be tempted to increase your sodium intake. But please don’t.

Remember that doctors advise people with heart problems to limit their salt consumption. For this reason, consider using other herbs and spices instead of salt. Also, don’t forget to read food labels as many processed foods contain high levels of salt.

3. Talk to your doctor about your fluid intake.

While water pills make you pee more frequently, you shouldn’t immediately think that you need to increase your fluid intake.

Likewise, don’t restrict your fluid intake to prevent yourself from urinating often.

The best course of action is to talk to your doctor about how much fluid you should have daily.

4. Consult your doctor about your potassium levels.

Since Thiazide and Loop diuretics cause you to lose potassium, an important mineral for muscle and nerve health, your doctor might ask you to eat more potassium-rich foods.

Potassium-sparing diuretics retain potassium. Since excessive potassium levels can adversely affect your heart rhythm, the doctor might advise you to refrain from using salt substitutes as they are usually high in potassium.

5. Take note of side-effects.

Diuretics may result in headaches, dehydration, and dizziness. They might also lead to muscle cramps, erectile dysfunction, and joint disorders.

If you experience these side effects, especially when they already interfere with your daily routine, don’t hesitate to consult your doctor.

Learn more about Heart Health here.


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Hello Health Group does not provide medical advice, diagnosis or treatment.


1 Thiazide Diuretics, https://www.ncbi.nlm.nih.gov/books/NBK532918/, Accessed October 8, 2021

2 Heart Disease Drug Therapy, https://www.cedars-sinai.org/programs/heart/conditions/treatments/drug-therapy.html, Accessed October 8, 2021

3 When are potassium-sparing diuretics indicated in the management of hypokalemia (low potassium level)?, https://www.medscape.com/answers/242008-160542/when-are-potassium-sparing-diuretics-indicated-in-the-management-of-hypokalemia-low-potassium-level, Accessed October 8, 2021

4 Study recommends diuretics as drugs of choice for stage one hypertension, https://www.pchrd.dost.gov.ph/14-r-d-updates/3205-study-recommends-diuretics-as-drugs-of-choice-for-stage-one-hypertension, Accessed October 8, 2021

5 Diuretics, https://www.heartandstroke.ca/heart-disease/treatments/medications/diuretics, Accessed October 8, 2021

6 Diuretics, https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/in-depth/diuretics/art-20048129, Accessed October 8, 2021

7 Tips for taking diuretic medications, https://www.health.harvard.edu/heart-health/tips-for-taking-diuretic-medications, Accessed October 8, 2021

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Written by Lorraine Bunag, R.N. Updated 2 weeks ago
Fact Checked by Cesar Beltran