Diuretics: Therapeutic use
Last modified: Sunday, 31. May 2009 - 1:52 pm
Diuretics are prescribed in cases where excess fluids in bodily tissues (edema) cause illness, discomfort, or medical complications.
Medical conditions that may warrant the use of diuretics include:
Hypertension (high blood pressure)
A standard treatment for hypertension, diuretics flush excess water and sodium from the body. They also lower blood pressure by reducing the total volume of fluid in the bloodstream. A reduced total volume of blood means that the heart does not have to work as hard to circulate it through the body.
Often, diuretics are used in combination with other drugs to relieve hypertension. Types of diuretics used to treat hypertension include thiazides, such as chloroth-iazide (Diuril) and hydrochlorothiazide (Esidrex); potassium-sparing diuretics, such as spironolactone (Aldactone); and loop diuretics, such as furosemide (Lasix).
Congestive heart failure (CHF)
Congestive heart failure occurs when the pumping ability of the heart is impaired, and the heart itself becomes enlarged. This may be due to coronary artery disease, chronic hypertension, diabetes, arrhythmia (irregular heartbeat), infection, or a heart valve disorder. The result is edema, or swelling caused by fluid retention, a major symptom of congestive heart failure. Patients with CHF experience swollen legs, ankles, feet, and/or fluid in the lungs (pulmonary edema). Sometimes fluid builds up around other organs, such as the liver, as well. Loop diuretics such as furosemide (Lasix) are frequently prescribed to alleviate edema from congestive heart failure. Thiazide and potassium-sparing diuretics may also be prescribed.
Other drugs that may be prescribed in conjunction with diuretics for the treatment of CHF include vasodilators (drugs that dilate blood vessels, such as ACE inhibitors); inotropics (drugs that increase the heart’s ability to contract, such as digoxin); and beta blockers (drugs that inhibit the action of epinephrine, such as carvedilol).
Also known as water diabetes, diabetes insipidus (DI) is a rare chronic disease that causes excessive urination. If not properly treated, it can result in electrolyte imbalance and dehydration. It may be caused by a number of factors, including lithium use (a psychiatric drug used for bipolar disorder), neurological disease, or an inadequate amount of ADH (anti-diuretic hormone, or vasopressin, which is produced by the pituitary gland). DI caused by insufficient ADH is called central diabetes insipidus.
Nephrogenic diabetes insipidus, which occurs less often than central diabetes insipidus, is characterized by the inability of the kidneys to reabsorb water into the bloodstream. Treatment with thiazide or potassium-sparing diuretics can help maintain a fluid and electrolyte balance in some individuals with diabetes insipidus.
Diuretics may also be prescribed for a number of other disorders and conditions that trigger fluid retention, including:
• Nephrotic syndrome. Thiazide or loop diuretics are used in the treatment of this kidney disorder that causes increased protein in the urine.
• Cirrhosis. Potassium-sparing diuretics are frequently prescribed for the patients with this liver disease.
• Renal hypercalciuria (kidney stones). Thiazide diuretics such as metolazone (Zaroxolyn) that increase calcium levels in the body are used in the treatment of kidney stones.
• Water retention related to menstruation. Pamabrom, an ingredient in over-the-counter diuretic preparations, can relieve bloating related to a woman’s menstrual cycle.
Several studies have shown that thiazide diuretics prevent calcium loss in bones, which may improve bone density and protect against osteoporosis. Preliminary research also suggests that diuretics are helpful in preventing stroke. Further studies are needed to confirm these findings.