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Other drug names: A-Am An-Az B C-Ch Ci-Cz D-Dh Di-Dz E F G H I-J K-L M-Mh Mi-Mz N-Nh Ni-Nz O P-Pl Pm-Pz Q-R S-Sn So-Sz T-To Tp-Tz U-V W-Z 0-9   

Diuretics, Loop (Systemic)

Brand Names

Some commonly used brand names are:

In the U.S.-

In Canada-


For quick reference, the following loop diuretics are numbered to match the corresponding brand names.
This information applies to the following medicines:
1.  Bumetanide (byoo-MET-a-nide) ** ****�
2.  Ethacrynic Acid (eth-a-KRIN-ik AS-id)
3.  Furosemide (fur-OH-se-mide) **
**  Generic name product may be available in the U.S.
***  Generic name product may be available in Canada
*  Not commercially available in the U.S.
****�  Not commercially available in Canada


  • Antihypercalcemic  -- Bumetanide; Ethacrynic Acid; Furosemide
  • Antihypertensive  --Bumetanide; Ethacrynic Acid; Furosemide
  • Diagnostic aid adjunct, renal disease  -- Furosemide
  • Diuretic  -- Bumetanide; Ethacrynic Acid; Furosemide


Loop diuretics are given to help reduce the amount of water in the body. They work by acting on the kidneys to increase the flow of urine.

Furosemide is also used to treat high blood pressure (hypertension) in those patients who are not helped by other medicines or in those patients who have kidney problems.

High blood pressure adds to the work load of the heart and arteries. If it 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.

Loop diuretics may also be used for other conditions as determined by your doctor.

This medicine is available only with your doctor's prescription, in the following dosage forms:

  • Bumetanide
    • Tablets (U.S.)
  • Ethacrynic Acid
    • Oral solution (U.S. and Canada)
    • Tablets (U.S. and Canada)
  • Furosemide
    • Oral solution (U.S. and Canada)
    • Tablets (U.S. and Canada)
  • Bumetanide
    • Injection (U.S.)
  • Ethacrynic Acid
    • Injection (U.S. and Canada)
  • Furosemide
    • Injection (U.S. and Canada)

Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For loop diuretics, the following should be considered:

Allergies- Tell your doctor if you have ever had any unusual or allergic reaction to bumetanide, ethacrynic acid, furosemide, sulfonamides (sulfa drugs), or thiazide diuretics (water pills). Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy- Studies have not been done in pregnant women. However, studies in animals have shown this medicine to cause harmful effects.

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.

Breast-feeding- These medicines have not been reported to cause problems in nursing babies. Furosemide passes into breast milk; it is not known whether bumetanide or ethacrynic acid passes into breast milk.

Children- Although there is no specific information comparing the use of loop diuretics in children with use in any other age group, these medicines are not expected to cause different side effects in children than they do in adults.

Older adults- Dizziness, lightheadedness, or signs of too much potassium loss may be more likely to occur in the elderly, who are more sensitive to the effects of this medicine. Elderly patients may also be more likely to develop blood clots.

Other medicines- Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking loop diuretics, it is especially important that your health care professional know if you are taking any other medicines.

Other medical problems- The presence of other medical problems may affect the use of loop diuretics. Make sure you tell your doctor if you have any other medical problems, especially:
  • Diabetes mellitus (sugar diabetes)-Loop diuretics may increase the amount of sugar in the blood
  • Gout or
  • Hearing problems or
  • Pancreatitis (inflammation of the pancreas)-Loop diuretics may make these conditions worse
  • Heart attack, recent-Use of loop diuretics after a recent heart attack may increase the chance of side effects
  • Kidney disease (severe) or
  • Liver disease-Higher blood levels of the loop diuretic may occur, which may increase the chance of side effects
  • Lupus erythematosus (history of)-Ethacrynic acid and furosemide may make this condition worse

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:

  • If you are to take a single dose a day, take it in the morning after breakfast.
  • If you are to take more than one dose a day, take the last dose no later than 6 p.m., unless otherwise directed by your doctor.

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.

For patients taking the oral liquid form of furosemide:

  • This medicine is to be taken by mouth even if it comes in a dropper bottle. If this medicine does not come in a dropper bottle, use a specially marked measuring spoon or other device to measure each dose accurately, since the average household teaspoon may not hold the right amount of liquid.

For patients taking this medicine for high blood pressure :

  • In addition to the use of the medicine your doctor has prescribed, appropriate treatment for your high blood pressure may include weight control and care in the types of foods you eat, especially foods high in sodium. Your doctor will tell you which factors are most important for you. You should check with your doctor before changing your diet.
  • Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.
  • Remember that this medicine will not cure your high blood pressure but it does help control it. Therefore, you must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life . If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.

If this medicine upsets your stomach, it may be taken with meals or milk. If stomach upset (nausea, vomiting, or stomach pain) continues or gets worse, or if you suddenly get severe diarrhea, check with your doctor.


The dose of loop diuretics 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 loop diuretics. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets or teaspoonfuls of solution 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 taking loop diuretics .

    For bumetanide
  • For oral dosage form (tablets):
    • To lower the amount of water in the body:
      • Adults-0.5 to 2 milligrams (mg) once a day. Your doctor may increase your dose if needed.
      • Children-Dose must be determined by your doctor.
  • For injection dosage form:
    • To lower the amount of water in the body:
      • Adults-0.5 to 1 mg injected into a muscle or a vein every two to three hours as needed.
      • Children-Dose must be determined by your doctor.
    For ethacrynic acid
  • For oral dosage form (oral solution or tablets):
    • To lower the amount of water in the body:
      • Adults-50 to 200 milligrams (mg) a day. This may be taken as a single dose or divided into smaller doses.
      • Children-At first, 25 mg a day. Your doctor may increase your dose as needed.
  • For injection dosage form:
    • To lower the amount of water in the body:
      • Adults-50 mg injected into a vein every two to six hours as needed.
      • Children-Dose is based on body weight and must be determined by your doctor. The usual dose is 1 mg per kilogram (kg) (0.45 mg per pound) of body weight injected into a vein.
    For furosemide
  • For oral dosage form (oral solution or tablets):
    • To lower the amount of water in the body:
      • Adults-At first, 20 to 80 milligrams (mg) once a day. Then, your doctor may increase your dose as needed. Your doctor may tell you to take a dose once a day, two or three times a day, or every other day.
      • Children-Dose is based on body weight and must be determined by your doctor. The usual dose is 2 mg per kilogram (kg) (0.91 mg per pound) of body weight for one dose. Then, your doctor may increase your dose every six to eight hours as needed.
    • For high blood pressure:
      • Adults-40 mg two times a day. Your doctor may increase your dose.
  • For injection dosage form:
    • To lower the amount of water in the body:
      • Adults-At first, 20 to 40 mg injected into a muscle or a vein for one dose. Then, your doctor may increase your dose every two hours as needed. Once the medicine is working, the dose is injected into a muscle or a vein one or two times a day.
      • Children-Dose is based on body weight and must be determined by your doctor. The usual dose is 1 mg per kg (0.45 mg per pound) of body weight injected into a muscle or a vein for one dose. Your doctor may increase your dose every two hours as needed.
    • For very high blood pressure:
      • Adults-40 to 200 mg injected into a vein.

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.


To store this medicine:

  • Keep out of the reach of children.
  • Store away from heat and direct light.
  • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
  • Keep the oral liquid form of this medicine from freezing.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

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 may cause a loss of potassium from your body :

  • To help prevent this, your doctor may want you to:
    • eat or drink foods that have a high potassium content (for example, orange or other citrus fruit juices), or
    • take a potassium supplement, or
    • take another medicine to help prevent the loss of the potassium in the first place.
  • It is very important to follow these directions. Also, it is important not to change your diet on your own. This is more important if you are already on a special diet (as for diabetes), or if you are taking a potassium supplement or a medicine to reduce potassium loss. Extra potassium may not be necessary and, in some cases, too much potassium could be harmful.

To prevent the loss of too much water and potassium, tell your doctor if you become sick, especially with severe or continuing nausea and vomiting or diarrhea.

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

Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position . This is more likely to occur in the morning. Getting up slowly may help . When you get up from lying down, sit on the edge of the bed with your feet dangling for 1 or 2 minutes. Then stand up slowly. If the problem continues or gets worse, check with your doctor.

The dizziness, lightheadedness, or fainting is also more likely to occur if you drink alcohol, stand for long periods of time, exercise, or if the weather is hot. While you are taking this medicine, be careful to limit the amount of alcohol you drink. Also, use extra care during exercise or hot weather or if you must stand for long periods of time .

For diabetic patients :

  • This medicine may affect blood sugar levels. While you are using this medicine, be especially careful in testing for sugar in your blood or urine.

For patients taking this medicine for high blood pressure :

  • Do not take other medicines unless they have been discussed with your doctor . This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.

For patients taking furosemide :

  • Furosemide may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:
    • Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
    • Wear protective clothing, including a hat. Also, wear sunglasses.
    • Apply a sun block product that has a skin protection factor (SPF) of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your health care professional.
    • Apply a sun block lipstick that has an SPF of at least 15 to protect your lips.
    • Do not use a sunlamp or tanning bed or booth.
If you have a severe reaction from the sun, check with your doctor .

Side Effects of This Medicine

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:

  • Rare
    • Black, tarry stools;  blood in urine or stools;  cough or hoarseness;  fever or chills;  joint pain;  lower back or side pain;  painful or difficult urination ;  pinpoint red spots on skin;  ringing or buzzing in ears or any loss of hearing-more common with ethacrynic acid;  skin rash or hives;  stomach pain (severe) with nausea and vomiting;  unusual bleeding or bruising;  yellow eyes or skin ;  yellow vision-for furosemide only 

  • Signs and symptoms of too much potassium loss
    • Dryness of mouth;  increased thirst;  irregular heartbeat;  mood or mental changes;  muscle cramps or pain;  nausea or vomiting;  unusual tiredness or weakness ;  weak pulse 

Other 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. However, check with your doctor if any of the following side effects continue or are bothersome:

  • More common
    • Dizziness or lightheadedness when getting up from a lying or sitting position 

  • Less common or rare
    • Blurred vision;  chest pain-with bumetanide only;  confusion-with ethacrynic acid only;  diarrhea-more common with ethacrynic acid;  headache;  increased sensitivity of skin to sunlight-with furosemide only;  loss of appetite-more common with ethacrynic acid;  nervousness-with ethacrynic acid only;  premature ejaculation or difficulty in keeping an erection-with bumetanide only ;  redness or pain at place of injection;  stomach cramps or pain 

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

Additional Information

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, loop diuretics are used in certain patients with the following medical conditions:

  • Hypercalcemia (too much calcium in the blood)
  • Diagnostic aid for kidney disease

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.

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Last updated: Tue, 06 Jan 2009 00:20:03 GMT