Any drug that increases the flow of urine from the body. Diuretics promote removal of excess water, salts, poisons, and metabolic wastes to help relieve edema, kidney failure, or glaucoma. Most types act by decreasing the amount of fluid that is reabsorbed by the kidney's nephrons and passed back into the blood. Diuretics that allow the body to retain potassium are used for patients with hypertension or congestive heart failure.
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Loop diuretics have this ability, and are therefore often synonymous with high ceiling diuretics. Loop diuretics, such as furosemide, inhibit the body's ability to reabsorb sodium at the ascending loop in the kidney which leads to a retention of water in the urine as water normally follows sodium back into the extracellular fluid (ECF). Other examples of high ceiling loop diuretics include ethacrynic acid, torsemide and bumetanide.
Glucose, like mannitol, is a sugar that can behave as an osmotic diuretic. Unlike mannitol, glucose is commonly found in the blood. However, in certain conditions such as diabetes mellitus, the concentration of glucose in the blood exceeds the maximum resorption capacity of the kidney. When this happens, glucose remains in the filtrate, leading to the osmotic retention of water in the urine. Use of some drugs, especially stimulants may also increase blood glucose and thus increase urination.
The antihypertensive actions of some diuretics (thiazides and loop diuretics in particular) are independent of their diuretic effect. That is, the reduction in blood pressure is not due to decreased blood volume resulting from increased urine production, but occurs through other mechanisms and at lower doses than that required to produce diuresis. Indapamide was specifically designed with this in mind, and has a larger therapeutic window for hypertension (without pronounced diuresis) than most other diuretics.
|Examples||Mechanism||Location (numbered in distance along nephron)|
|-||Ethanol, Water||inhibits vasopressin secretion||1.|
|Acidifying salts||CaCl2, NH4Cl||1.|
| Arginine vasopressin|
receptor 2 antagonists
|amphotericin B, lithium citrate||inhibit vasopressin's action||5. collecting duct|
|Aquaretics||Goldenrod, Juniper||Increases blood flow in kidneys||1.|
|Na-H exchanger antagonists||dopamine||promote Na+ excretion||2. proximal tubule|
|Carbonic anhydrase inhibitors||acetazolamide, dorzolamide||inhibit H+ secretion, resultant promotion of Na+ and K+ excretion||2: proximal tubule|
|Loop diuretics||bumetanide, ethacrynic acid, furosemide, torsemide||inhibit the Na-K-2Cl symporter||3. medullary thick ascending limb|
|Osmotic diuretics||glucose (especially in uncontrolled diabetes), mannitol||promote osmotic diuresis||2. proximal tubule, descending limb|
|Potassium-sparing diuretics||amiloride, spironolactone, triamterene, potassium canrenoate.||inhibition of Na+/K+ exchanger: Spironolactone inhibits aldosterone action, Amiloride inhibits epithelial sodium channels||5. cortical collecting ducts|
|Thiazides||bendroflumethiazide, hydrochlorothiazide||inhibit reabsorption by Na+/Cl- symporter||4. distal convoluted tubules|
|Xanthines||caffeine, theophylline||inhibit reabsorption of Na+, increase glomerular filtration rate||1. tubules|
Diuretic suggested as initial hypertension treatment: increased use of diuretics could save billions.(thiazides recommended as initial therapy)
Mar 01, 2003; The largest hypertension trial ever conducted is recommending thiazide Diuretics as initial therapy over newer, more...