The action of spironolactone is to interfere with sodium reabsorption in distal renal tubules by competitively inhibiting the action of aldosterone. Oct 04, 2018 loop diuretics and thiazide diuretics are stronger than potassium sparing diuretics with regard to making the kidneys pass out more fluid. Amiloride hydrochloride is a new, orally administered, potassiumsparing diuretic with mild natriuretic and diuretic properties. Concomitant administration of potassiumsparing diuretics and ace inhibitors or. Potassiumsparing diuretics are medicines that increase diuresis urination without the loss of potassium.
Loop diuretics and potassium sparing diuretics have limited roles in the management of hypertension although. Some drugs in this class antagonize the actions of aldosterone aldosterone receptor antagonists at the distal segment of the distal tubule. Used by themselves, potassium sparing diuretics exert only a mild diuretic effect because the collecting duct reabsorbs only 25% of filtered sodium. Oct 27, 2012 the benzothiadiazines and related compounds have a moderate diuretic action spread over a longer period, whilst the potassium sparing diuretics, triamterene, amiloride and spironolactone, have only a weak diuretic effect but a marked ability to diminish urinary potassium excretion. List of potassiumsparing diuretics potassium sparing. Before considering the specific action of diuretic drugs on the transport of water and electrolytes in the renal tubule, brief attention should be given to their effects on glomerular filtration since such effects may influence to a major extent the magnitude. Because of its steroid hormonelike structure, spironolactone can mildly activate the nuclear receptors for testosterone and progesterone leading to gynecomastia and impotence in men as well as menstrual irregularities in women. Aldactone spironolactone is a specific pharmacologic. Osmotic diuretics and carbonic anhydrase inhibitors are used in acute settings to lower intracranial andor intraocular pressure e. Mechanism of action most diuretics produce diuresis by inhibiting the reabsorption of sodium at different segments of the renal tubular system this is accomplished by altering how the kidney handles sodium. Loop diuretics and potassium sparing diuretics have limited roles in the management of hypertension although accumulating evidence suggests that potassiumsparing diuretics may have an important place in apparently resistant hypertension. Therefore, the more sodium is in the organism, the more water is in the patients body, and this leads to increased. The most concerning adverse effect of all potassium sparing diuretics is hyperkalemia that can rapidly become fatal as potassium levels rise. Thiazide diuretics uses, list, thiazide mechanism of action.
Loop diuretics are medications that help remove extra fluid volume from the blood through increased urination. Potassium sparing diuretics nursing implications and drug. Potassiumsparing diuretics pharmacology the essential. Potassiumsparing diuretics are often combined with either a loop diuretic or a thiazide diuretic. They are generally weak diuretics and work by interfering with the sodiumpotassium exchange in the distal convoluted tubule of the kidneys or as an antagonist at the aldosterone receptor. Potassium sparing diuretics are medicines that increase diuresis urination without the loss of potassium. The former prevents the production of proteins that are normally synthesized in. Used by themselves, potassiumsparing diuretics exert only a mild diuretic effect because the collecting duct reabsorbs only 25% of filtered sodium. They can also potentiate the effects of other proximally acting diuretics e. Potassiumsparing diuretics pharmacology nursing mechanism. Potassiumsparing diuretics an overview sciencedirect. The potassiumsparing diuretics act via mechanisms in the renal tubule that are distinct from those of other diuretic agents.
As a result, there is increased excretion of sodium and water and an associated loss of potassium. Their mechanism depends on renal prostaglandin production. Breastfeedingall potassiumsparing diuretics may be distributed into breast milk use in the elderlyincreased risk of hyperkalemia other medications, especially angiotensinconverting enzyme ace inhibitors, cyclosporine, digoxin, other potassiumsparing diuretics, potassiumcontaining medications or supplements, or lithium. Papich dvm, ms, dacvcp, in saunders handbook of veterinary drugs fourth edition, 2016. They are occasionally used to counteract the potassiumwasting effects of thiazides. Describe the mechanism of action of diuretics essay. Potassiumsparing diuretics are diuretics that result in increased urine production and also lower blood pressure while increasing serum levels of potassium. They are less potent diuretic agents therefore potassium sparing diuretics may combine with other diuretics to prevent the loss of potassium and further increase in diuretic effects. Potassiumsparing diuretics such as spironolactone, amiloride, and. Diuretics, potassiumsparing drug information, professional. Potassium sparing diuretics, which block the epithelial sodium channel enac, are widely prescribed for hypertension as a secondline drug in patients taking other diuretics e. Before considering the specific action of diuretic drugs on the transport of water and electrolytes in the renal tubule, brief attention should be given to their effects on glomerular filtration since such effects may influence to a major extent the magnitude of the diuresis. This classification of diuretics is based on their site of action in the kidneys. The thick ascending limb of henles loop is the site of action of loop diuretics.
Diuretics knowledge for medical students and physicians. Potassium sparing diuretics university health network. Potassiumsparing diuretics information, uses and side. Potassiumsparing diuretics these agents increase diuresis, but without causing potassium to be lost from the body. However, they also increase the amount of potassium passed out of the body through the kidneys. They are generally weak diuretics and work by interfering with the sodium potassium exchange in the distal convoluted tubule of the kidneys or as an antagonist at the aldosterone receptor. Mechanism of action, pharmacokinetics, adverse effects, and therapeutic uses of amiloride hydrochloride, a new potassiumsparing diuretic. The potassium sparing diuretics act via mechanisms in the renal tubule that are distinct from those of other diuretic agents. What this medicine is why you need to take it what side effects to watch for this fact sheet was created by the university health network pharmacy department. The potassiumsparing diuretics act via mechanisms in the renal tubule that are distinct. Potassiumsparing diuretics an overview sciencedirect topics. Potassiumsparing diuretics are diuretic drugs that do not promote the secretion of potassium.
Site of action of diuretic drugs kidney international. Potassium sparing diuretics nursing implications and drug study. Potassiumsparing diuretics act on the distal portion of the distal con voluted tubule and in the collecting duct, inhibiting sodiumpotassium. Thiazide diuretics uses, list, thiazide mechanism of. Diuretic therapy in heart failure current approaches. Potassiumsparing diuretics refer to a class of compounds that interfere with sodium resorption within principal cells of the late distal tubule and collecting duct see. The action of spironolactone is to interfere with sodium reabsorption in distal renal tubules by competitively inhibiting the action of. Potassiumsparing diuretics definition of potassiumsparing. Capitals indicate lifethreatening, underlines indicate most frequent. Unlike loop and thiazide diuretics, some of these drugs do not act directly on sodium transport. Mechanism of action, pharmacokinetics, adverse effects, and. The benzothiadiazines and related compounds have a moderate diuretic action spread over a longer period, whilst the potassiumsparing diuretics, triamterene, amiloride and spironolactone, have only a weak diuretic effect but a marked ability to diminish urinary potassium excretion. The term potassiumsparing refers to an effect rather than a mechanism or location. Low levels of potassium and magnesium in the blood can result in abnormal heart rhythms, particularly in those who are also taking digoxin in addition to a thiazide.
Mechanism of action, pharmacokinetics, adverse effects. Loop diuretics mechanism of action and adverse effects. Because only a small fraction of urinary sodium is absorbed at this segment, potassiumsparing diuretics are rather weak in terms of their sodium diuresis capacity. Potassium sparing diuretics information for patients read this medicine fact sheet to learn about. Interactions between antihypertensive drugs and other medications. These are diuretics which do not promote the secretion of potassium into the urine. Principles of diuretic action site of action is located on the luminal surface of the tubule extensively bound to serum albumin transported into the proximal tubule lumen by active secretion organic acid secretory pathway.
Some of these effects can be used to treat disorders like hypercalcemia, hypocalcemia or hyperaldosteronism. Outcome data with potassiumsparing diuretics is lacking. A new nonsteroidal mineralocorticoid blocker, finerenone, is currently in phase 3 clinical trials. Potassium sparing diuretics include drugs that block apical sodium channels amiloride and triamterene and those that antagonize mineralocorticoid receptors spironolactone and eplerenone.
Potassium sparing diuretics are often combined with either a loop diuretic or a thiazide diuretic. Amiloride hydrochloride is a new, orally administered, potassium. Loop diuretics and thiazide diuretics are stronger than potassiumsparing diuretics with regard to making the kidneys pass out more fluid. Nonpostassium sparing diuretics may cause potassium a mineral in your body to be lost along with the fluid. The commonly used classes of diuretics are loop, thiazide, and potassium sparing diuretics, and carbonic anhydrase inhibitors. The main importance of these diuretics is that they are potassium sparing. The potassium sparing diuretics are competitive antagonists that either compete with aldosterone for intracellular cytoplasmic receptor sites, or directly block sodium channels specifically epithelial sodium channels enac by amiloride. Diuretics work on the kidneys to eliminate water and. Thiazide diuretics can lower potassium and magnesium blood levels since they are both eliminated in urine. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Diuretics are a group of drugs that induce increased production of urine. Diuretic dosing and adverse effects are discussed separately. Potassiumsparing diuretics definition of potassium. Diuretics acting by modifying the content of the filtrate. The collecting duct is the major site of action in the kidney of. Potassiumsparing diuretics are available as proprietary formula tions combined with a thiazide or loop diuretic. Amiloride is marketed as combination tablets with loop or thiazide diuretics as a means of avoiding hypokalemia. Loop diuretics and potassium sparing diuretics have limited roles in the management of hypertension although accumulating evidence suggests that potassium sparing diuretics may have an important place in apparently resistant hypertension. Diuretic drugs are typically classified first according to their predominant site of action along the nephron and second by the mechanism by which they inhibit transport. See time course of loop and thiazide diureticinduced electrolyte complications.
They are used in the treatment of hypertension and in congestive heart failure. Other potassiumsparing diuretics directly inhibit sodium channels associated with the. There is a third class of diuretic that is referred to as potassium sparing diuretics. Potassiumsparing diuretics reduce the amount of water in your system without affecting levels of potassium. Potassium sparing diuretics caused diuresis without loss of potassium unlike other diuretics. Most of the different types of potassiumsparing diuretics work in a specific area of the kidney, where they can block potassium excretion while increasing the elimination of sodium and water.
Carbonic anhydrase inhibitors are rarely used in the management of hypertension or heart failure and hence will not be discussed in detail. Mechanism of action sodium is the most troubling electrolyte for patients with hypertension, as one atom of sodium binds four molecules of water. Heart failure, diuretic therapy, diuretic resistance, loop diuretics, thiazide diuretics, potassiumsparing diuretics. Therefore, the more sodium is in the organism, the more water is in the patients body, and this leads to increased blood volume and consequently high blood pressure. One widely used example of a potassium sparing diuretic is spironolactone. This paper focuses on the mechanism of action, pharmacodynamics, antihypertensive effects, adverse effects, interactions and contraindications of loop diuretics and potassiumsparing agents including. Prescription of a potassium sparing agent is more effective than the use of. Legend ksparing diuretic mechanisms in the cortical collecting duct.
Potassiumsparing diuretics, which block the epithelial sodium channel enac, are widely prescribed for hypertension as a secondline drug in patients taking other diuretics e. These unique properties result in biologic effects specific to drugs within the class that can be complementary to other diuretics, especially kaliuretic agents such as loop diuretics and thiazides. Loop diuretics examples bumetamide furosemide torasemide mechanism of action. Clinical pharmacology in diuretic use american society of. They are occasionally used to counteract the potassium wasting effects of thiazides.
Diuretics, commonly called water pills, are drugs that promote diuresis, that is increased production of urine. Loop diuretics include drugs such as furosemide and bumetanide. Heart failure, diuretic therapy, diuretic resistance, loop diuretics, thiazide diuretics, potassium sparing diuretics. Loop diuretics pharmacology all the facts in one place.
The loop diuretics furosemide, bumetanide, and torsemide act from the lumen to inhibit the nak2cl cotransporter nkcc2, encoded by slc12a1 along the thick ascending limb and. Nonpotassium sparing diuretics university of toronto. A common feature of all diuretics is their natriuretic action, which leads to a decrease in total body sodium. Combination tablets are more expensive but may improve compliance by reducing the number of tablets to be taken. If you need this medicine for another problem, your health care provider will give you more information.
Depending on the class, diuretics act on different renal structures and lead to varying changes in the volume and composition of urine as well as electrolyte balance. As diuretics are often given to people with heart failure, and loss of potassium can lead to ventricular fibrillations, then diuretics that promote loss of potassium can often exacerbate the situation. Nonpotassium sparing diuretics pronouced di uret ics. Its primary site of action is the distal tubule of the nephron where it selectively blocks sodium transport, thereby inhibiting sodium. The term potassium sparing refers to an effect rather than a mechanism or location. The most commonly used diuretics with a pronounced diuretic effect are thiazides, loop diuretics, and potassium sparing diuretics. Potassium sparing diuretics these are diuretics which do not promote the secretion of potassium into the urine. Potassium sparing diuretics these agents increase diuresis, but without causing potassium to be lost from the body. This henles loop is characterized by being impermeable to water, although it powerfully and actively transports the sodium, chloride and potassium ions via the. Describe the mechanism of action of diuretics essay example. One widely used example of a potassiumsparing diuretic is spironolactone. Loop diuretics act on the nephron mainly in the thick ascending links of the loop of. This is an indication for potassium correction usually by coadministration of a potassium sparing diuretic.
The potassiumsparing diuretics are very weak natriuretics indeed, capable of a maximum excretion of 12% of filtered sodium. Amiloride blocks the epithelial sodium channel thereby inhibits sodium reabsorption at this site and prevent loss of potassium thus called potassium sparing diuretics. Thiazide diuretics can increase the risk of lithium eskalith, lithobid toxicity by reducing the kidneys ability to. Clinical pharmacology in diuretic use american society.
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