Diuretics

What is a diuretic?

Diuretics ― also known as water pills ― are medicines that help you move extra fluid and salt out of your body. They make you pee more frequently, which is why you should take them in the morning if you can. You may need to take diuretics once or twice a day at the same time each day.

Water pills make your kidneys take away your body’s extra salt and water by putting them into your urine (pee). By clearing out extra fluids from your body, diuretics lower the amount of fluid in your blood that your heart has to pump. This helps people whose kidneys aren’t working well or who have swelling (edema), heart failure or high blood pressure.

When you have heart failure, your heart can’t pump as well as it should, allowing fluids to build up. So having less fluid to pump eases the demand on your heart. Having less fluid that needs to get through your blood vessels helps reduce blood pressure. Water pills also help your blood vessels get wider, which is another way they help lower your blood pressure.

People usually take diuretics by swallowing pills, but your healthcare provider can give some of these medicines through an IV in your arm during a hospital stay.

Types of diuretics

Types of diuretics include:

• Thiazide diuretics (hydrochlorothiazide or chlorthalidone)
• Loop diuretics (furosemide or bumetanide) — providers prefer these potent drugs for people with a low GFR (glomerular filtration rate)
• Potassium-sparing diuretics (triamterene or amiloride) — these don’t let you lose too much potassium
• Two types in one pill (triamterene and hydrochlorothiazide) — these keep you from losing too much potassium

Different diuretics work by affecting certain parts of your kidneys to keep them from reabsorbing salt. Thiazide diuretics and potassium-sparing diuretics work in one part of your kidney. Loop diuretics work in another.

Thiazide diuretics are the most common diuretics that Americans use to treat high blood pressure. Out of this type, hydrochlorothiazide is the drug providers prescribe most often.

What do diuretics treat?

Diuretic medications can help with:

• High blood pressure
• Heart failure
• Cardiomyopathy (heart muscle disease)
• Pulmonary edema (fluid buildup in your lungs)
• Ascites (fluid buildup in your belly)
• Kidney failure
• Nephrotic syndrome (too much protein in your pee)
• High intraocular pressure (fluid buildup in your eye)
• Increased intracranial pressure (fluid buildup in your brain)

What are the advantages of a diuretic?

Diuretic pills give many people good results, especially for treating high blood pressure. Also, people generally don’t have bad side effects with diuretics. Some natural options, like herbal supplements, may help, but water pills can provide more reliable results. Although the caffeine in natural diuretics like coffee or tea makes you pee more, the effects don’t last long.

What are the side effects?

Possible side effects of diuretics include:

• Upset stomach, gas or diarrhea
• Loss of appetite
• Hair loss
• Fatigue
• Headache
• Gout
• Difficulty getting an erection
• Low potassium (for some types)
• Muscle cramps
• Higher blood sugar in people with diabetes
• Unbalanced electrolytes

Most people can take diuretics without getting serious problems from them. But your healthcare provider will want to make sure your kidneys are working right and your potassium level is normal when you’re taking water pills. If you’re pregnant, breastfeeding (chestfeeding) or having problems with your kidneys or liver, discuss the risks of diuretics with your provider.

Diuretic drugs make you pee more often than you would if you weren’t taking one. If you’re taking too high a dose of a diuretic or not drinking enough fluids, you can get dehydrated. If you don’t drink enough fluids, diuretics can lead to constipation.

How soon do diuretics start working?

Diuretics usually start working an hour or two after you take them. They affect you less as the day goes on, with hardly any effect after six hours for some. It might take a couple of weeks for your blood pressure to decrease.

How can I take care of myself while taking a diuretic?

While you’re taking a water pill, you can take care of yourself in these ways:

• Limit the amount of salt you eat.
• Make sure you don’t get dehydrated.
• Get blood or urine tests your provider orders to check kidney function.
• Check with your provider instead of changing your dose on your own.
• Keep follow-up appointments with your provider.

When should I see my healthcare provider?

Contact your provider when you have diuretic side effects that bother you, like:

• Heart palpitations
• Dizziness
• Dehydration

You should also let your provider know if you plan to become pregnant (or learn that you are) so they can find the safest blood pressure medicine for you.