The condition known as heart failure (HF) usually involves a gradual loss of heart function rather than a sudden, complete stop. The heart keeps pumping, just not as well. In HF, blood backs up in the heart and circulatory system and causes swelling, also called "edema" or "congestion", usually in the lower legs, but possibly in other parts of the body like the hands, abdomen, or lungs. Because less blood circulates to the kidneys, the body retains more water and salt, interfering with the heart's ability to beat and causing blood pressure to rise.

When drug treatment is needed, diuretics (also known as "water pills") are often used to relieve swelling or fluid retention, improve exercise ability, and maintain heart function. Diuretics work by increasing the amount of salt and water eliminated by the kidneys, thus reducing blood pressure and allowing the heart to pump blood more effectively. Diuretic treatment usually starts with low doses that are increased if necessary to increase urine output and reduce body weight. For HF patients, doses of diuretics are often higher than doses of the same drugs used to treat hypertension. Two or more different types of diuretics can be used together and diuretics are frequently given with other types of drugs such as ACE inhibitors (ACE-I).

Some patients may develop "diuretic resistance"--meaning a diuretic gradually loses its effectiveness as HF gets worse. Not taking diuretics correctly, worsening kidney function, and diuretic interactions with other drugs also contribute to diuretic resistance. In addition, long-term use of a certain type of diuretic, called the loop diuretics, actually may change kidney tissues so the drugs are not as effective.

Drugs in this Class
Furosemide Solution for Injection ()
Torsemide Injection (Demadex Injection)
Metolazone Tablets (Zaroxolyn Tablets)
Hydrochlorothiazide and Triamterene Capsules (Dyazide, HCTZ and Triamterene Capsules)
Furosemide Oral Solution ()
Hydrochlorothiazide Capsules (HCTZ Capsules, Microzide Capsules)
Torsemide Tablets (Demadex Tablets)
Amiloride and Hydrochlorothiazide ()
Bumetanide Tablets (Bumex)
Indapamide ()
Triamterene (Dyrenium)
Chlorthalidone Tablets (Chlorthalidone, Thalitone)
Bumetanide Injection ()
Furosemide Tablets (Lasix Tablets)

Summarizing the Evidence

Thiazide and Thiazide-Like Diuretics
Chlorthalidone, Hydrochlorothiazide, Chlorothiazide, Indapamide, and Metolazone

• Thiazides may be effective enough to control mild HF for people with normal kidney function. They affect a part of the kidneys where large amounts of sodium and water are absorbed back into the body. By blocking the re-absorption process, these drugs force more sodium and more water into the urine to be removed from the body. Thiazides may also relax the muscles in blood vessel walls, allowing blood to flow more easily. All thiazide and thiazide-like diuretics are thought to be comparably effective.

• Chlorthalidone, specifically, has shown a greater decrease in heart failure risk versus a calcium channel blocker (amlodipine) or an ACE-inhibitor (lisinopril)--other drugs commonly used in the treatment of heart failure--during the first year of a recent trial. Although the ACE-I was as effective as chlorthalidone after one year of therapy, this diuretic was shown to be more efficacious than the calcium channel blocker.

Loop Diuretics
Bumetanide, Furosemide, Torsemide, and Ethacrynic Acid

• Patients with more advanced HF, low kidney function, and/or more severe edema probably do better on a loop or combination diuretic. Unfortunately, loop diuretics are also more likely to promote the elimination of calcium, magnesium and--especially-- potassium. Shortages of any of these essential minerals can cause serious problems such as irregular heartbeat. However, doctors can closely monitor the levels of these minerals in the body to help avoid potential problems. Often times a potassium supplement is taken along with the loop diuretic to ensure potassium does not get too low. All loop diuretics are thought to be comparably effective.

Potassium-Sparing Diuretics
Amiloride and Triamterene

• Much weaker than the thiazides or the loop diuretics, the potassium-sparing diuretics are not usually given alone as treatment for HF. They are sometimes added to a loop or thiazide diuretic to ensure potassium levels do not get too low. This class of diuretics should be used carefully and require close monitoring in individuals that are already getting potassium supplementation. All potassium-sparing diuretics are thought to be comparably effective.

Combination Diuretics
Amiloride and Hydrochlorothiazide and Triamterene and Hydrochlorothiazide

• Since they are not very effective alone, the potassium-sparing diuretics that are used in the U.S. are almost always combined into a single tablet or capsule with another diuretic--usually hydrochlorothiazide (often abbreviated "HCTZ"). All combination diuretics are thought to be comparably effective.

Dosing and Administration

• Thiazide and thiazide-like diuretics are each typically taken once daily.

• Loop diuretics are each typically taken once or twice daily. For more severe symptoms of heart failure, loop diuretics may have to be taken more frequently.

• Potassium-sparing diuretics are each typically taken once daily except triamterene which is taken twice daily.

• Combination diuretics are each typically taken once daily except for triamterene and hydrochlorothiazide which can be taken up to twice daily.

Generic Availability

• All currently available diuretics have generic equivalents.

Drug Interactions

Some interactions between medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how the drugs interact and the severity of the interaction, please use our Drug Interactions Checker.

Side Effects

To view specific side effect information, please use our Side Effect Checker.

Additional Information
References

1. Drug Facts and Comparisons. St. Louis, MO. 2007.
2. Johnson JA, Parker RB, Patterson JH. Heart Failure. In: DiPiro JT, Talbert RL, Yee GC, et al., (Eds). Pharmacotherapy: a pathophysiologic approach. 6th ed. New York: McGraw-Hill, 2002:219-260.
3. Heart Failure Society of America (HFSA) practice guidelines. HFSA guidelines for management of patients with heart failure caused by left ventricular systolic dysfuntion -- pharmacological approaches. J Card Fail. 2006;12:e1-e122.
4. Drugdex Database. In: Gelman CJ, Rumack BH, editors. Denver: Micromedex Inc. 2007.
5. Davis BR, Piller LB, Cutler JA, et al. Role of diuretics in the prevention of heart failure: the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. Circulation. 2006 May 9;113(18):2166-8.
6. ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult Circulation. 2005;112:e154-e235.

Last Updated: April 2008

Note: The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist, or other healthcare professional. It should not be construed to indicate that the use of the product is safe, appropriate, or effective for you. Consult your healthcare professional before taking any medication.

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