Health Guide
Drug Guide

Diuretic, potassium sparing (Oral route)

Brand Names:

Dosage Forms:

Uses of This Medicine:

Potassium-sparing diuretics are commonly used to help reduce the amount of water in the body. Unlike some other diuretics, these medicines do not cause your body to lose potassium.

Amiloride and spironolactone are also used to treat high blood pressure (hypertension). High blood pressure adds to the workload of the heart and arteries. If the condition continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.

Spironolactone is also used to help increase the amount of potassium in the body when it is getting too low.

Potassium-sparing diuretics help to reduce the amount of water in the body by acting on the kidneys to increase the flow of urine. This also helps to lower blood pressure.

These medicines can also be used for other conditions as determined by your doctor.

Potassium-sparing diuretics are available only with your doctor's prescription.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, spironolactone is used in certain patients with the following medical conditions:

Before Using This Medicine:


Tell your doctor if you have ever had any unusual or allergic reaction to medicines in this group or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


This medicine has been tested in children and, in effective doses, has not been shown to cause different side effects or problems in children than it does in adults.

Older adults

Signs and symptoms of too much potassium are more likely to occur in the elderly, who are more sensitive than younger adults to the effects of this medicine.


Studies have not been done in pregnant women. However, this medicine has not been shown to cause birth defects or other problems in animals.

In general, diuretics are not useful for normal swelling of feet and hands that occurs during pregnancy. Diuretics should not be taken during pregnancy unless recommended by your doctor.


Although amiloride, spironolactone, and triamterene may pass into breast milk, these medicines have not been reported to cause problems in nursing babies.

Other medicines

Using medicines in this class with any of the following medicines is not recommended. Your doctor may decide not to treat you with a medication in this class or change some of the other medicines you take.

Using medicines in this class with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Other interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Other medical problems

The presence of other medical problems may affect the use of medicines in this class. Make sure you tell your doctor if you have any other medical problems, especially:

Proper Use of This Medicine:

This medicine may cause you to have an unusual feeling of tiredness when you begin to take it. You may also notice an increase in the amount of urine or in your frequency of urination. After you have taken the medicine for a while, these effects should lessen. In general, to keep the increase in urine from affecting your sleep:

However, it is best to plan your dose or doses according to a schedule that will least affect your personal activities and sleep. Ask your health care professional to help you plan the best time to take this medicine.

To help you remember to take your medicine, try to get into the habit of taking it at the same time each day.

If this medicine upsets your stomach, it may be taken with meals or milk. If stomach upset (nausea, vomiting, stomach pain or cramps) continues, check with your doctor.

For patients taking this medicine for high blood pressure:


The dose medicines in this class will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


Keep out of the reach of children.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Do not keep outdated medicine or medicine no longer needed.

Precautions While Using This Medicine:

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly.

This medicine does not cause a loss of potassium from your body as some other diuretics (water pills) do. Therefore, it is not necessary for you to get extra potassium in your diet, and too much potassium could even be harmful. Since salt substitutes and low-sodium milk may contain potassium, do not use them unless told to do so by your doctor.

Check with your doctor if you become sick and have severe or continuing nausea, vomiting, or diarrhea. These problems may cause you to lose additional water, which could be harmful, or to lose potassium, which could lessen the medicine's helpful effects.

Before having any kind of surgery (including dental surgery) or emergency treatment, tell the medical doctor or dentist in charge that you are taking this medicine.

Before you have any medical tests, tell the doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine

For patients taking this medicine for high blood pressure:

For patients taking triamterene:

Side Effects of This Medicine:

In rats, spironolactone has been found to increase the risk of tumors. It is not known if spironolactone increases the chance of tumors in humans.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

For amiloride, spironolactone, and triamterene
Skin rash or itching
shortness of breath
For spironolactone and triamterene only (in addition to effects listed above)
Cough or hoarseness
fever or chills
lower back or side pain
painful or difficult urination
For triamterene only (in addition to effects listed above)
Black, tarry stools
blood in urine or stools
bright red tongue
burning, inflamed feeling in tongue
cracked corners of mouth
lower back pain (severe)
pinpoint red spots on skin
unusual bleeding or bruising
Signs and symptoms of too much potassium
irregular heartbeat
numbness or tingling in hands, feet, or lips
shortness of breath or difficult breathing
unusual tiredness or weakness
weakness or heaviness of legs

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
(less common with amiloride and triamterene)
Nausea and vomiting
stomach cramps and diarrhea
Less common
For amiloride, spironolactone, and triamterene
For amiloride and spironolactone only (in addition to effects listed above)
Decreased sexual ability
For amiloride only (in addition to effects listed above)
muscle cramps
For spironolactone only (in addition to effects listed above for spironolactone)
Breast tenderness in females
deepening of voice in females
enlargement of breasts in male
inability to have or keep an erection
increased hair growth in females
irregular menstrual periods
For triamterene only (in addition to effects listed above for triamterene)
Increased sensitivity of skin to sunlight
Signs and symptoms of too little sodium
dryness of mouth
increased thirst
lack of energy

For male patients: Spironolactone sometimes causes enlarged breasts in males, especially when they take large doses of it for a long time. Breasts usually decrease in size gradually over several months after this medicine is stopped. If you have any questions about this, check with your doctor.

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Last Updated: 6/12/2013

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