diuretic
American Heritage Dictionary:
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di·u·ret·ic
(dī'ə-rĕt'ĭk) 
adj.
Tending to increase the discharge of urine.
n.
A substance or drug that tends to increase the discharge of urine.
adj.
Tending to increase the discharge of urine.
n.
A substance or drug that tends to increase the discharge of urine.
[Middle English diuretik, from Old French diuretique, from Late Latin diūrēticus, from Greek diourētikos, from diourein, to pass urine : dia-, dia- + ourein, to urinate.]
diuretically di'u·ret'ic·al·ly adv.Britannica Concise Encyclopedia:
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diuretic
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.
For more information on diuretic, visit Britannica.com.
Oxford Food & Nutrition Dictionary:
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diuretics
Substances that increase the production and excretion of urine. They may be either compounds that occur naturally in foods (including caffeine and alcohol), or drugs used medically to reduce the volume of body fluid (e.g. in the treatment of hypertension and oedema).
Oxford Food & Fitness Dictionary:
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diuretic
A diuretic is any substance (including alcohol and caffeine) that increases the elimination of fluid from the body through urination. It is also the name of a pharmacological class of drugs banned by the International Olympic Committee and many other sports federations.
Diuretic drugs form an important part of the treatment for certain disorders such as oedema (a process which results in accumulation of fluid and swollen tissues). Diuretics have also been used by sports people and slimmers to lose weight quickly. Weight-lifters, jockeys, wrestlers, and boxers use diuretics so they can meet strict weight controls. Diuretics are included in diet pills (sometimes called water tablets) to accelerate weight loss, but their effects are temporary.
Chronic use of diuretics can be dangerous. The elimination of large volumes of water may result in a loss of mineral salts and increase the risk of dehydration, hypertension, and cardiovascular disorders.
Oxford Companion to the Body:
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diuretics
Diuresis is increased urine flow, and diuretics are substances which elicit diuresis. Strictly speaking, by this definition, water is a diuretic, because ingestion of excess water increases urine flow. In medicine and pharmacology, however, the term ‘diuretic’ has come to have a more specific meaning. Diuretics are therapeutic agents which act on the kidneys. They are used to reduce the extracellular fluid volume (see body fluids), and they also reduce the effective circulating blood volume. They are widely used in patients with hypertension and with congestive heart failure. In the latter group, diuretics are used to reduce oedema (tissue swelling due to excess fluid). They have also been used as an aid to slimming, though this is not medically approved.
In the first 20 years of the twentieth century, the diuretics used were theophylline (found in dandelions) and caffeine (in tea and coffee). In 1919, mercurial drugs came into use, followed in the 1950s by thiazides. Details follow of diuretics still widely used.
In the kidneys, water and dissolved substances are filtered from the circulating blood into the microscopic nephrons; most of this water is normally reabsorbed into the blood, whilst the solutes are variously dealt with — retained or rejected according to need.
Water reabsorption from the fluid in the tubules of the nephrons is dependent primarily on reabsorption of sodium ions — the more sodium ions are retrieved, the more water accompanies them back into the blood. The term ‘diuretic’ therefore generally refers to agents which inhibit tubular sodium reabsorption, which occurs to the greatest extent in the first (proximal) part of the tubules through which the fluid flows. With the exception of osmotic diuretics (see below), most diuretics are organic acids, and as such are secreted from the blood into the fluid in the proximal tubules, whence they exert their effects. There are a number of different chemical types of diuretic, and several sites of action within the nephron.
Osmotic diuretics
A straightforward cause of diuresis is the filtration of large amounts of any substance which cannot be reabsorbed by the nephrons. In diabetes mellitus, for example, the plasma glucose concentration (blood sugar) is increased, and the amount of glucose filtered overwhelms the nephrons' reabsorptive mechanism, so that glucose is excreted in the urine, and there is an increased volume of urine. The glucose is acting as an osmotic diuretic. Likewise, a completely non-reabsorbable sugar, mannitol, is often used as an osmotic diuretic agent. So, how do osmotic diuretics work?
When the proximal tubule reabsorbs sodium ions, water normally follows by osmosis, causing the concentration of non-reabsorbable solutes in the tubular fluid to increase. This limits water reabsorption. If there is additional solute in the fluid (as in the glucose example above) less water than normal follows the sodium ions. This discrepancy results in a lowering of sodium ion concentration in the tubular fluid, and in turn a diminished rate of sodium ion reabsorption. Hence there is increased excretion of both sodium ions and water.
Loop diuretics
Most of the diuretics introduced in recent years are ‘loop’ diuretics — their primary sites of action in the kidneys are the loops of Henle, which the fluid reaches after leaving the proximal tubule. Here sodium ions are normally ‘pumped’ out of this fluid and into the fluid which surrounds the loops and the next channels, the collecting ducts, helping to establish an osmotic gradient which will draw more water out of the incoming fluid. Ethacrynic acid, bumetanide, piretanide, and frusemide are loop diuretics. They act by blocking this movement of sodium, so both sodium and water reabsorption are impaired, and more remains to reach the urine. Loop diuretics also increase potassium loss in the urine, so they are often combined with a dietary potassium supplement.
Other diuretics
Spironolactone competes with the hormone aldosterone for receptor sites in the cells of the distal tubules of the nephrons, which the fluid reaches from the loops of Henle. Since aldosterone promotes absorption of sodium from the tubular fluid, and secretion of potassium into it, spironolactone opposes these actions, enhancing excretion of sodium in the urine — and of water along with it — and decreasing potassium excretion. The diuretics triamterene and amiloride have similar overall effects, though by different molecular mechanisms.
— Chris Lote
See also kidneys; urine; water balance.
Oxford A-Z of Medicinal Drugs:
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diuretics
A class of drugs that increase the volume of urine (diuresis) by promoting the excretion of salts (especially sodium and potassium) and water via the kidneys. Diuretics are used to reduce the oedema due to salt and water retention in disorders of the kidneys, heart, or liver. They are also used, alone or in combination with other drugs, in the treatment of high blood pressure (see hypertension). The use of diuretics can result in potassium deficiency; this is corrected by the simultaneous administration of a potassium supplement or by adding another diuretic with a potassium-sparing effect, such as amiloride or triamterene. (Potassium is essential for the normal functioning of nerves and muscles; low concentrations of potassium cause weakness, confusion, and in severe cases abnormal heart rhythms.) The main classes of diuretics are the loop diuretics, thiazide diuretics, and potassium-sparing diuretics.
| dithranol, disulfiram, distigmine bromide | |
| dobutamine hydrochloride, docetaxel, docusate sodium |
Columbia Encyclopedia:
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diuretics
diuretic (dī'yərĕt'ĭk), drug used to increase urine formation and output. Diuretics are prescribed for the treatment of edema (the accumulation of excess fluids in the tissues of the body), which is often the result of underlying disease of the kidneys, liver, lungs, or heart (e.g., congestive heart failure). They are also used to treat hypertension (high blood pressure) and glaucoma. They act on the kidneys, modifying the absorption and excretion of water and electrolytes such as sodium and potassium. Types of diuretics include thiazides, loop diuretics, and potassium-sparing diuretics.
Oxford Dictionary of Biochemistry:
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diuretic
- producing an increase in the volume of urine.
- any agent that increases the volume of urine.
| diuresis, dithiothreitol, dithioerythritol | |
| diurnal, divalent metal transporter 1, divergent evolution |
Saunders Veterinary Dictionary:
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diuretic
1. increasing urine excretion or the amount of urine.
2. an agent that promotes urine secretion.
- aldosterone antagonist d. — affects tubular function by blocking the sodium retention activity of aldosterone. See also spironolactone.
- aminouracil d's — heterocyclic compounds similar to xanthines and with similar effects. See xanthine diuretics (below).
- benzothiazide d's — exert their effect on the proximal part of the renal tubule preventing resorption of sodium. Called also thiazide diuretics. The best known members of the group are chlorothiazide and its derivatives.
- carbonic anhydrase inhibitor d's — inhibit carbonic anhydrase activity and inhibit ion exchange mechanisms especially that of sodium and potassium ions. See also acetazolamide.
- loop of Henle d's — affect the resorption of sodium in the ascending loop of Henle. Called also loop diuretic. See also furosemide, ethacrynate sodium.
- mercurial d. — now largely displaced; the mode of action is to interfere with tubular enzyme systems so that tubular resorption is blocked. Overuse causes permanent renal damage.
- osmotic d's — produce a very rapid loss of sodium and water by inhibiting their reabsorption in the kidney tubules and the loop of Henle. Mannitol is clinically the most useful of these diuretics, but it has some serious side-effects, such as pulmonary edema and congestive heart failure.
- potassium-retaining d's — appear to act directly on renal tubular function. See also triamterene.
- xanthine d's — have effect of stimulating cardiac activity but also have a direct effect on the renal tubules. See also theophylline.
Mosby's Dental Dictionary:
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diuretic
(dī′yōōret′ik)
n
n
1. a drug that increases the formation of urine. adj 2. pertaining to the increased formation of urine.
Random House Word Menu:
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categories related to 'diuretic'
- Physiology - diuretic: substance that inhibits fluid reabsorption in kidney, causing increase in excreted urine
- PHARMACOLOGY - diuretic: agent that promotes excretion of salt and water by kidneys
See crossword solutions for the clue Wikipedia on Answers.com:
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Diuretic
| Diuretic | |
|---|---|
| Drug class | |
 This illustration shows where some types of diuretics act, and what they do. |
|
| Use | Forced diuresis, hypertension |
| ATC code | C03 |
A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.
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Contents
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Medical uses
In medicine, diuretics are used to treat heart failure, liver cirrhosis, hypertension and certain kidney diseases. Some diuretics, such as acetazolamide, help to make the urine more alkaline and are helpful in increasing excretion of substances such as aspirin in cases of overdose or poisoning. Diuretics are often abused by sufferers of eating disorders, especially bulimics, in attempts at weight loss.[1]
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.
Types
High ceiling loop diuretic
High ceiling diuretics are diuretics that may cause a substantial diuresis – up to 20%[2] of the filtered load of NaCl and water. This is huge when compared to normal renal sodium reabsorption which leaves only ~0.4% of filtered sodium in the urine.
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 nephron which leads to an excretion of water in the urine whereas water normally follows sodium back into the extracellular fluid (ECF). Other examples of high ceiling loop diuretics include ethacrynic acid, torsemide and bumetanide.
Thiazides
Thiazide-type diuretics such as hydrochlorothiazide act on the distal convoluted tubule and inhibit the sodium-chloride symporter leading to a retention of water in the urine, as water normally follows penetrating solutes. Frequent urination is due to the increased loss of water that has not been retained from the body as a result of a concomitant relationship with sodium loss from the convoluted tubule. The short-term anti-hypertensive action is based on the fact that thiazides decrease preload, decreasing blood pressure. On the other hand the long-term effect is due to an unknown vasodilator effect that decreases blood pressure by decreasing resistance.
Carbonic anhydrase inhibitors
Carbonic anhydrase inhibitors inhibit the enzyme carbonic anhydrase which is found in the proximal convoluted tubule. This results in several effects including bicarbonate retention in the urine, potassium retention in urine and decreased sodium absorption. Drugs in this class include acetazolamide and methazolamide.
Potassium-sparing diuretics
These are diuretics which do not promote the secretion of potassium into the urine; thus, potassium is spared and not lost as much as in other diuretics. The term "potassium-sparing" refers to an effect rather than a mechanism or location; nonetheless, the term almost always refers to two specific classes that have their effect at similar locations:
- Aldosterone antagonists: spironolactone, which is a competitive antagonist of aldosterone. Aldosterone normally adds sodium channels in the principal cells of the collecting duct and late distal tubule of the nephron. Spironolactone prevents aldosterone from entering the principal cells, preventing sodium reabsorption. A similar agent is potassium canreonate.
Calcium-sparing diuretics
The term "calcium-sparing diuretic" is sometimes used to identify agents that result in a relatively low rate of excretion of calcium.[3]
The reduced concentration of calcium in the urine can lead to an increased rate of calcium in serum. The sparing effect on calcium can be beneficial in hypocalcemia, or unwanted in hypercalcemia.
The thiazides and potassium-sparing diuretics are considered to be calcium-sparing diuretics.[4]
- The thiazides cause a net decrease in calcium lost in urine.[5]
- The potassium-sparing diuretics cause a net increase in calcium lost in urine, but the increase is much smaller than the increase associated with other diuretic classes.[5]
By contrast, loop diuretics promote a significant increase calcium excretion.[6] This can increase risk of reduced bone density.[7]
Osmotic diuretics
Compounds such as mannitol are filtered in the glomerulus, but cannot be reabsorbed. Their presence leads to an increase in the osmolarity of the filtrate. To maintain osmotic balance, water is retained in the urine.
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 (hyperglycemia) exceeds the maximum reabsorption capacity of the kidney. When this happens, glucose remains in the filtrate, leading to the osmotic retention of water in the urine. Glucosuria causes a loss of hypotonic water and Na+ leading to a hypertonic state with signs of volume depletion such as: dry mucosa, hypotension, tachycardia, and decreased turgor of the skin. Use of some drugs, especially stimulants may also increase blood glucose and thus increase urination.
Low ceiling diuretics
The term "low ceiling diuretic" is used to indicate that a diuretic has a rapidly flattening dose effect curve (in contrast to "high ceiling", where the relationship is close to linear). It refers to a pharmacological profile, not a chemical structure. However, there are certain classes of diuretic which usually fall into this category, such as the thiazides.[8]
Mechanism of action
Classification of common diuretics and their mechanisms of action:
Chemically, diuretics are a diverse group of compounds that either stimulate or inhibit various hormones that naturally occur in the body to regulate urine production by the kidneys. Herbal medications are not inherently diuretics. They are more correctly called aquaretics.
Adverse effects
The main adverse effects of diuretics are hypovolemia, hypokalemia, hyperkalemia, hyponatremia, metabolic alkalosis, metabolic acidosis and hyperuricemia.[9]
| Adverse effect | Diuretics | Symptoms |
|---|---|---|
| Hypovolemia | ||
| hypokalemia | ||
| Hyperkalemia | ||
| hyponatremia | ||
| metabolic alkalosis |
|
|
| metabolic acidosis |
|
|
| hypercalcemia | ||
| hyperuricemia |
See also
References
- ^ Smith, Mary. "Ms.". Registered Nurse / Gym Instructor. diureticsoverthecounter. http://diureticsoverthecounter.com/. Retrieved Oct 17, 2011.
- ^ Drug Monitor – Diuretics
- ^ Shankaran S, Liang KC, Ilagan N, Fleischmann L (April 1995). "Mineral excretion following furosemide compared with bumetanide therapy in premature infants". Pediatr. Nephrol. 9 (2): 159–62. doi:10.1007/BF00860731. PMID 7794709.
- ^ Bakhireva LN, Barrett-Connor E, Kritz-Silverstein D, Morton DJ (June 2004). "Modifiable predictors of bone loss in older men: a prospective study". Am J Prev Med 26 (5): 436–42. doi:10.1016/j.amepre.2004.02.013. PMID 15165661. http://linkinghub.elsevier.com/retrieve/pii/S0749379704000406.
- ^ a b Champe, Pamela C.; Richard Hubbard Howland; Mary Julia Mycek; Harvey, Richard P. (2006). Pharmacology. Philadelphia: Lippincott William & Wilkins. pp. 269. ISBN 0-7817-4118-1.
- ^ Rejnmark L, Vestergaard P, Pedersen AR, Heickendorff L, Andreasen F, Mosekilde L (January 2003). "Dose-effect relations of loop- and thiazide-diuretics on calcium homeostasis: a randomized, double-blinded Latin-square multiple cross-over study in postmenopausal osteopenic women". Eur. J. Clin. Invest. 33 (1): 41–50. doi:10.1046/j.1365-2362.2003.01103.x. PMID 12492451. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0014-2972&date=2003&volume=33&issue=1&spage=41.
- ^ Rejnmark L, Vestergaard P, Heickendorff L, Andreasen F, Mosekilde L (January 2006). "Loop diuretics increase bone turnover and decrease BMD in osteopenic postmenopausal women: results from a randomized controlled study with bumetanide". J. Bone Miner. Res. 21 (1): 163–70. doi:10.1359/JBMR.051003. PMID 16355285. http://www.jbmronline.com/doi/abs/10.1359/JBMR.051003?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dncbi.nlm.nih.gov.
- ^ Mutschler, Ernst (1995). Drug actions: basic principles and therapeutic aspects. Stuttgart, German: Medpharm Scientific Pub. pp. 460. ISBN 0-8493-7774-9.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar Boron, Walter F. (2004). Medical Physiology: A Cellular And Molecular Approach. Elsevier/Saunders. pp. 875. ISBN 1-4160-2328-3.
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This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Translations:
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Diuretic
Dansk (Danish)
adj. - diuretisk, vanddrivende
n. - urindrivende middel
Nederlands (Dutch)
diuretisch (het urineren stimulerend), (mv) diuretica (middelen ter bevordering van het urineren)
Français (French)
adj. - diurétique
n. - diurétique
Deutsch (German)
n. - harntreibendes Mittel, Diuretikum
adj. - harntreibend, diuretisch
Ελληνική (Greek)
n. - (ιατρ.) διουρητικό (φάρμακο)
adj. - (ιατρ.) διουρητικός
Português (Portuguese)
n. - diurético (m)
adj. - diurético
Русский (Russian)
мочегонное средство, мочегонный
Español (Spanish)
adj. - diurético
n. - diurético
Svenska (Swedish)
n. - urindrivande medel
adj. - urindrivande
中文（简体）(Chinese (Simplified))
利尿的, 利尿剂
中文（繁體）(Chinese (Traditional))
adj. - 利尿的
n. - 利尿劑
한국어 (Korean)
adj. - 오줌이 잘 나오게 하는
n. - 이뇨제
日本語 (Japanese)
adj. - 利尿の
n. - 利尿剤
العربيه (Arabic)
(الاسم) مادة أو دواء مدرة للبول ( طبيه) (صفه) مدر للبول
עברית (Hebrew)
adj. - משתן, גורם מתן שתן
n. - סם משתן
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The Oxford Companion to the Body. Copyright © 2001, 2003 by Oxford University Press. All rights reserved.
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