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8 Tips for Taking Water Pills Safely

Diuretics can help manage high blood pressure and other conditions

spinner image pack of pills with inscription "Diuretic Medication" for treatment of cardiovascular diseases near EKG
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Diuretics are one of the oldest classes of medications. Often known as water pills, they have been in used in modern medicine since the 1950s and 60s, and are widely prescribed today for a number of conditions.  ​

Thiazide diuretics, in particular, are often recommended as the initial treatment for high blood pressure, which affects almost half of American adults. These medications help relax arteries and reduce pressure. Other classes of diuretics, such as loop and potassium sparing, may be used to treat conditions such as heart or liver failure, tissue swelling, glaucoma, and some kidney disorders, including kidney stones.​ 

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​If you are taking diuretics, it is important to understand their purpose and potential risks. If not used appropriately, they may cause electrolyte imbalances, dehydration, and reduced kidney function. To ensure safe and effective use of these medications, we consulted a nephrologist, geriatrician, cardiologist and a doctor of pharmacy to come up with eight tips to follow when taking water pills.​ ​

1. Know that various types of diuretics have different effects on urination.​ ​

“Diuretics sort of mean increasing the urine volume — so making people pee more,” said Zac Cox, a professor in the department of pharmacy practice at Lipscomb University in Nashville, Tennessee. “It'll sort of range from mild to almost insignificant where you don't really notice any difference, all the way to very prominent changes in urination.”

​​​However, diuretics don’t just change the volume of urine; they change what's in the urine.​ 

​For example, they can change the way the body absorbs salt, causing it to be removed through urine instead of being absorbed into the body. Meanwhile, other classes can either lower or raise potassium levels in the body depending on how they affect urination.​ ​ ​

2. Schedule routine blood tests to detect potential electrolyte imbalances.​ ​​

Diuretics can cause electrolyte deficiencies because of their effect on how the body absorbs them. ​​

Usually, a deficiency can be replenished with a supplement such as potassium, one of the most common electrolytes lost. But changing your dosage or the diuretic prescribed may also improve electrolyte levels.​ 

​“Some people try to eat more foods that are rich in potassium, bananas or things like that,” said Cox. “Usually, you can't eat enough of that to get your losses, but it can help.”​ ​ ​ 

3. Drink plenty of fluids.​ 

​Taking water pills can heighten the dehydration in older adults who in general usually don't drink enough water, said Luigi Ferrucci, a geriatrician and scientific director of the National Institute on Aging.​ 

​“But you don't want to drink too much because the diuretics may alter the way that relative water and salt are handled,” said Donald Molony, a nephrologist at UTHealth Houston and Memorial Hermann-Texas Medical Center. “You may end up with a state in which you dilute down your salt to a level that is not as favorable for good health. That’s called hyponatremia.”​ ​


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He recommends between 48 and 62 ounces of fluid a day for those with normal kidney function. But water intake is something that should be consulted with a doctor, especially when suffering from impaired renal function or other rare conditions. ​ ​ 

​“We're sort of shooting for that Goldilocks principle of not too hot, not too cold, just right,” Cox said. ​ ​ 

4. Avoid alcohol to prevent the worsening of side effects.​ ​ ​

When you drink alcohol, it can affect some hormones in your body that help regulate your water balance. One hormone in particular, called antidiuretic hormone, or vasopressin, is affected by alcohol, which can lead to an imbalance of salt and water. This hormone causes water retention, and some evidence suggests excessive release of it due to alcohol intake can cause kidney damage, Molony said.​ ​

“Alcohol is something that should be handled with care,” he added.​ ​

5. Don’t rely on natural diuretics. They may not be as effective.​ ​

Hibiscus, dandelion, ginger, parsley and caffeine are natural diuretics, but it's crucial to speak with a doctor to first identify the underlying cause of fluid retention or swelling before taking them. ​ ​ 

​“Say it's, for example, heart failure. There are a number of other medications that are so much more important to use to change what’s going on in the heart than just treating the symptom of that,” Cox said. “So, it would be akin to putting a Band-Aid over an infected wound.”​ 

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​Relying on a natural diuretic may require consuming excessive amounts of the substance, which can lead to other negative side effects and would require electrolytes to be monitored with the help of a doctor. ​ ​ ​

6. You may need to adjust your dosage during hot weather.​ ​

Since people tend to sweat more in hot weather, more water is lost from the body. So, it may be necessary to adjust the dosage of medication during the summer months.​ ​ 

​“Especially in older age, the sense of thirst is reduced. So, you don't really perceive that you're getting dehydrated,” Ferrucci said. “Talk to your doctor to see whether the same amount of diuretic you're taking during the winter is also okay during the summer.”​ ​ ​

7. Talk to your doctor about all of your medications, including other diuretics.​ ​

When a practitioner prescribes a diuretic they are likely unaware of other medications prescribed by a different doctor or natural diuretics you take on your own. ​ 

​“It’s important that we know what you’re taking so we know how to adjust going forward,” said Erika Feller, a cardiologist at MedStar Health in Baltimore. “If there’s another agent that may be contributing to the diuresis or preventing diuresis, we need to know because it would change our management, potentially.” ​ 

8. Be aware of your salt intake and discuss it with your doctor ​ ​

Lowering your salt intake can be an effective way to reduce blood pressure when taking a diuretic. However, it's important to note that decreasing salt consumption may also result in a loss of potassium, which would necessitate adjusting both your diuretic regimen and salt intake.​ 

​“[Salt intake] should be a conversation between the individual and their clinic if they're therapeutically on diuretics,” Molony said.

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