What are Water Pills?

Author: Mark Parkinson RPh:  President  AFC-CE

Credit Hours 1- Approximate time required: 60 min.


Educational Goal:

To provide a better understand of what water pills are. 

Educational Objectives:

Define water pills and diuretics.

List the uses of diuretics. 

Instruct how diuretics work in the body

Tell what caregivers need to know about diuretic medication.


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   The information presented in this activity is not meant to serve as a guideline for patient management. All procedures, medications, or other courses of diagnosis or treatment discussed or suggested in this article should not be used by care providers without evaluation of their patients’ Doctor. Some conditions and possible contraindications may be of concern. All applicable manufacturers’ product information should be reviewed before use. The author and publisher of this continuing education program have made all reasonable efforts to ensure that all information contained herein is accurate in accordance with the latest available scientific knowledge at the time of acceptance for publication. Nutritional products discussed are not intended for the diagnosis, treatment, cure, or prevention of any disease.


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What are Water Pills? 

Just about everyone in the care business has heard of water pills. But if you look at your residents’ medication list, you will not find anything labeled as a water pill.  First, one doctor tells the patient this medication is a water pill. Then a nurse mentions that the medication is a diuretic. Then your pharmacist will counsel you that the medication is one of several different classes of medications referred to as water pills. What’s going on? One of the more common medications that care providers have to deal with are so-called water pills. What are water pills? What do they do? How do they work? Most importantly, what do caregivers have to know about them?


To help clarify the situation, let’s start off with a definition and medical terminology. The term “water pills” is everyday slang for the medical term diuretic. A diuretic is anything that causes an increase of the production of urine. To the common man, it may Image result for sour facesound better to say, “I have to take my water pills” rather than “I have to take my urine pills.” Ugh, that does sound unpleasant. It would be more accurate to say, “I have to take my ‘get rid of my extra water by increasing my urine output’ pills.” That’s way too long so most people just say water pills. When communicating with other medical personnel, it is more professional for caregivers to use the correct term of “diuretic.”  That’s how I will refer to it for the rest of the article. After all, you are a medical professional.


Diuretics have been around for a long time. They were first discovered when it was noticed that certain sulfa antibiotics made patients go the bathroom more. Before that time, it was difficult to remove unneeded water from the body. So specialized medications were developed to take advantage of this side effect. Many decades later, there is a proliferation of diuretics in multiple drug classes. Most of them now have cheap generics, which make them all the more favorable to use as first-line therapy for many illness and conditions.

Diuretics are used in the treatment of heart failure, liver cirrhosis, hypertension (high blood pressure), influenza, water poisoning (too much water), certain kidney diseases, and tissue swelling (ankle swelling or other edemas). They are also used to help excrete unwanted substances by increasing urine output, like in aspirin overdose cases. 

They are often misused by patients to lose water weight and mask illegal drug use. That information is particularly useful for mental health homes. They have to watch for diuretic misuse in their anorexic and bulimic residents and those who try to hide the self-treatment of mental illnesses with mood-altering drugs. 

How They Work

It might seem a bit of a stretch for adult foster caregivers to learn how medications work. I assure you, it’s not. For you, it’s not about making therapeutic decisions; it’s about monitoring for effect. It’s part of your job to observe and report anything out of the ordinary.

I would like for you to consider the following questions about water pills and your residents: “How do you know what is unusual if you don’t know what the medication does? Is that mid-day nap just daytime drowsiness or a side effect of the medication? Is that demand for additional glasses of water mean the diuretic is working too well?  Is that new diuretic going to make your resident wobbly on their feet and possibly fall and hurt themselves? The answer to all of these questions is maybe yes. Wouldn’t your job be easier if you knew that beforehand and could watch for those diuretic medication effects?

First things first, to monitor for effect, you have to know which medication is a diuretic. The drug lists and medication information you receive probably will not readily notify you that a medication has a diuretic effect, so I will.


Common Diuretic Medications



Many of these medications are combined with other drugs, especially blood pressure and heart meds. It is also common to combine different classes of diuretics into one pill.

Caffeine is also a diuretic.  Over-the- counter water pills are most likely just caffeine pills. Too much glucose in the blood can also make you pee more because water follows sugar.

Water also follows salt, which is how most of these medications work. To understand how, let’s briefly discuss the science of osmosis. If you pour water on a slug, all the water will be pulled out and it will turn into a gooey mess. If you put salt on meat, the water will be pulled out and the meat will get salt cured. Water always flows to where there is salt. If you want to pull water past a membrane, put a bunch of salt on one side and the water will flow through the membrane toward the salt. We call that process osmosis. Let’s now talk about how the body uses osmosis to get rid of water. It all happens in your kidneys.

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Kidney Anatomy and Physiology

The kidneys are two bean-shaped organs, about the size of your fist. They are located just below the rib cage on either side of the spine, toward the outside of your back.  All of your blood flows into and out of the kidneys several times a day. When the waste-filled blood comes in to the organ, it flows into millions of filtering units called nephrons.  Each nephron starts with a globe-like sieve called a glomerulus. It screens out the bigger blood elements like the red blood cells and proteins. The rest of the waste-filled liquid flows into loop-shaped tubules. By the end of the tubules, all that remains is the waste that flows into the bladder through the ureters.  The cleaned fluid is then put back into the blood stream.

You might have heard that your kidneys act like a filter to remove waste products from the body. It’s a bit more complicated than that. A filter prevents material from flowing through it. We want to get rid of the waste, not retain it. So the kidney is designed to let most of the liquid elements of our blood flow into tubules. As the liquid flows through the tubules, the kidneys pull back in what our bodies need. What’s leftover collects in the bladder and we void it as urine. Here’s the interesting part. The kidneys do not pump the water back in. They pull back the salts. Water naturally follows the salts by osmosis, and we are able to reabsorb the water and the salts we need to retain. Yes, that is very cool and more importantly that explains a few things about high blood pressure control, salt intake, and diuretic medication effects. 

Effects of Diuretics

A major way your body is set up to control blood pressure is by controlling how much salt is taken back in at the kidney’s nephrons.  If the body needs to lower the pressure of the blood, one way it reduces it is by reducing how much salt is taken back in the kidneys. More salt in the urine means more water flows into the bladder.

Modern medicine has learned to take advantage of that mechanism. Doctors are able to reduce fluid retention, lower blood pressure, and reduce the burden on internal organs, especially the heart.  The easiest way to do this is by reducing our salt intake. The less salt in the blood stream, the less fluid is retained in the blood. That is why the doctor will recommend a sodium-restricted diet as first-line therapy for many illnesses. If that is not enough, then the doctor can prescribe diuretic medications to kick the effect up a notch or two.

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What the Caregiver Has to Know

Adult foster care providers are everybody’s helper. You are in the business of serving everyone. You serve the patient by ensuring a lifestyle that is as healthy and normal as possible. You serve the doctor by monitoring their patient and notifying them when something seems wrong. It all starts with knowing your residents and knowing what the doctor is trying to do for them. As you know, though, that is easier said than done. Adult foster care providers are at the far end of the medical pecking order. Far too often, no one bothers to tell you what’s going on medically with your resident. It’s up to you to find out. It’s part of your job to ask the questions and keep asking until you know. Let me provide you with some answers.


When you see a diuretic medication on a resident’s med list, the doctor is trying to remove bodily fluids. The doctor hopes that by doing so, a desired effect will be produced, most likely lowering blood pressure, reducing edema, and making it easier for a weakened organ to function.

What you as a care provider have to monitor for is:

  • Blood pressure - I recommend a digital home blood pressure reading kit. What you’re looking for is trends over time. Don’t worry about single spikes or dips. For more info, see my other CE on blood pressure.
  • Fluid retention - I recommend that you use a seamstress measuring tape and measure the area of edema. For example, measure ankles to see if the edema is going away. For a more general measurement of water retention, keep track of the resident’s weight.
  • For more involved cases, you might have to measure the resident’s fluid intake.

Side Effects

Diuretic medications can have other effects on the body that the doctor never intended. Most are just annoyances that the just has to endure. Some are temporary and will go away by themselves as the body gets used to the medication. Some are very serious that you the caregiver must watch for.

I recommend that you read the side effect info that comes with any new prescription.  Watch for the listed side effects for a couple of months.  After that, just watch for the unusual occurrences in the resident’s life.

Generally speaking watch for:

  • The medication is working too well and the resident’s blood pressure dips too low. This can be seen in the resident’s unusually tired responses or an upswing in the number of naps. Also look for grouchiness brought on by confusion or listlessness.
  • If the blood pressure is normal but the confusion and unexplained grouchiness continue, it still might be the medication. It might be throwing off the resident’s electrolytes (blood chemicals, like the different salts). Notify the doctor and ask the question about the electrolytes and the diuretics.
  • Low blood pressure and electrolyte imbalance can also cause headaches. If the resident’s headache continues even when treated or they keep coming back, that’s a red flag.
  • Muscle spasms are also a red flag. They are possibly a signal that there isn’t enough salt in the blood for the muscles to function properly.
  • Vomiting and seizures can also occur and are an obvious occurrence that should automatically be called into the doctor.
  • If nausea occurs, that’s a judgement call on your part. So many things can cause nausea that it could be just a false alarm. Things that might help you decide whether to call the doctor or not are when the nausea occurs (soon after the medication is take) or if the nausea returns over and over again.
  • Extra thirst and dehydration is also a judgement call. Keep plenty of water available for the resident to drink just as part of your normal good caregiving techniques. Then the problem will never become a concern.

Image result for special notesA Few Special Notes

A gout attack can be caused by dehydration and electrolyte imbalances. They are very painful, so any occurrence should be called in to the doctor. Attacks usually occur in the big toe. If they continue to happen, it would be prudent to ask the doctor if the diuretics are contributing to the problem.

Many diuretic medications work on or are affected by the body’s prostaglandins. They are chemicals produced by the body to regulate many bodily functions. NSAIDs also work on the prostaglandins.  An increase in NSAID use may cause more diuretic side effects. Generally, the occasional use will not cause any issues, but if the MAR’s prn chart shows a lot of NSAID use, then go back to monitoring closely for diuretic side effects.

It has been shown that diuretic medication use can cause diabetic problems. If you take care of a diabetic, monitor closely blood sugars when using diuretics.

As a general rule of thumb, diuretics are taken in the morning so as not to disturb sleeping patterns by having to go to the bathroom.

Some diuretics bleed of potassium, others are called potassium sparing. I would talk to the doctor about any salt substitutes that you use in cooking. Some of them are potassium chloride.  There is the potential for messing up the residents electrolytes.



Water pills, who knew that they would be that complicated? At least now you understand them better and are more prepared to monitor for effects. Just keep track of the blood pressure, take the edema measurement, and monitor for thirst, drowsiness, grouchiness, confusion, and muscle cramps and things will be fine.

As always, good luck in your caregiving.

Mark Parkinson RPh



Diuretic. Wikipedia the Free Encyclopedia. 13 April 2017,https://en.wikipedia.org/wiki/Diuretic

  1. High Blood Pressure and Diuretics (Water Pills). WebMD.com. October 12, 201. http://www.webmd.com/hypertension-high-blood-pressure/guide/diuretic-treatment#1
  2. Heart failure - fluids and diuretics. National Institutes of Health U.S. National Library of Medicine, MedlinePlus https://medlineplus.gov/ency/patientinstructions/000112
  3. Dr Chloe Borton, Dr Gurvinder Rull. Diuretics. Patient. 30 December 2016. https://patient.info/doctor/diuretics
  4. James Kelly, John Chambers. Inappropriate use of loop diuretics in elderly patients. Age and Ageing 2000:29:489-493 http://ageing.oxfordjournals.org/content/29/6/489.full.pdf
  5. Mark D. Coggins, PharmD. Evaluating Potential Diuretic Overuse. Today’s Geriatric MedicineVol. 6 No. 6 P. 5. http://www.todaysgeriatricmedicine.com/archive/110113p5.shtml
  6. Richard E. Klabunde, PhD. Diuretics. Cardiovascular Pharmacology Concepts 10/29/2012 http://cvpharmacology.com/diuretic/diuretics
  7. Medical Definition of Diuretic. MedicineNet.com. http://www.medicinenet.com/script/main/art.asp?articlekey=7103
  8. Mary Ellen Ellis. Diuretics: What To Know. Healthline. November 7, 2016. http://www.healthline.com/health/diuretics#introduction1
  9. Your Kidneys and How They Work. The National Institute of Diabetes and Digestive and Kidney Disease, NIH. https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work
  10. How Your Kidneys Work. National Kidney Foundation. https://www.kidney.org/kidneydisease/howkidneyswrk


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