Don’t be fooled by their name — water pills pack a powerful punch. Doctors use them for all sorts of conditions. But water pills, also known as diuretics, are mostly used to lower blood pressure. And they’re excellent at doing just that.
That’s a good thing, because almost half of all adults in the U.S. have high blood pressure. When you have high blood pressure, your heart has to work harder to pump blood throughout the body. Your kidneys also have a tougher time removing salt and water from the body. That turns into a vicious cycle. More fluid in the body means your blood pressure keeps going up.
Diuretics help your kidneys flush out extra salt and water, explains Alyssa Wozniak, PharmD. She’s a clinical assistant professor at D’Youville School of Pharmacy in Buffalo, New York. And, yes, they make you pee more often as the body gets rid of the extra fluid. But when you have less fluid in your blood vessels, your heart doesn’t have to pump as hard. And that lowers your blood pressure.
Doctors also prescribe water pills when your legs or feet swell up from too much fluid in your body. That happens to people with kidney disease or heart failure.
There are 3 main types of water pills. They work in slightly different ways and for different conditions. Here’s what you need to know about each one. (Be sure to download our free mobile app to save on diuretics and any other medications you take.)
Types of diuretics
The 3 types of water pills work in slightly different ways. And doctors may prescribe them for different reasons, too.
Thiazide diuretics (hydrochlorothiazide, chlorothiazide, metolazone)
What they’re best for: High blood pressure
How they work: Thiazide diuretics stop the kidneys from reabsorbing sodium, says Wozniak. Instead, the sodium, along with the extra water and potassium, exits the body when you go to the bathroom. Potassium and sodium are electrolytes that help your kidneys work.
What you need to know: You’ll need to get regular blood tests. That way, your doctor can check your sodium and potassium levels to make sure you’re not losing too much of those electrolytes, Wozniak explains. If you are, your provider may put you on another type of diuretic or blood pressure medication.
Loop diuretics (bumetanide, ethacrynic acid, furosemide)
What they’re best for: Various conditions, depending on the type of diuretic
- Bumetanide treats high blood pressure, congestive heart failure and kidney disease.
- Ethacrynic acid treats high blood pressure, as well as fluid retention caused by medical problems such as cancer, heart disease, kidney disease or liver disease.
- Furosemide is used to treat swelling caused by heart disease, kidney disease or liver disease.
How they work: Loop diuretics stop a specific area of your kidney (the loop of Henle) from reabsorbing sodium chloride. That helps the kidneys flush out salt, water and other electrolytes, such as potassium and magnesium, says Wozniak.
What you need to know: Your doctor will check your kidney function and electrolyte levels by giving you blood and urine tests from time to time, Wozniak notes.
