Potassiumsparing diuretics pharmacology the essential. The commonly used classes of diuretics are loop, thiazide, and potassium sparing diuretics, and carbonic anhydrase inhibitors. Their mechanism depends on renal prostaglandin production. The potassium sparing diuretics act via mechanisms in the renal tubule that are distinct from those of other diuretic agents. Some of these effects can be used to treat disorders like hypercalcemia, hypocalcemia or hyperaldosteronism.
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. They can also potentiate the effects of other proximally acting diuretics e. Oct 04, 2018 loop diuretics and thiazide diuretics are stronger than potassium sparing diuretics with regard to making the kidneys pass out more fluid. Potassiumsparing diuretics definition of potassiumsparing. Prescription of a potassium sparing agent is more effective than the use of. Potassiumsparing diuretics, which block the epithelial sodium channel enac, are widely prescribed for hypertension as a secondline drug in patients taking other diuretics e. Mechanism of action, pharmacokinetics, adverse effects, and therapeutic uses of amiloride hydrochloride, a new potassiumsparing diuretic. Clinical pharmacology in diuretic use american society. Diuretics, potassiumsparing drug information, professional. Mechanism of action, pharmacokinetics, adverse effects. 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. Diuretics, commonly called water pills, are drugs that promote diuresis, that is increased production of urine. The main importance of these diuretics is that they are potassium sparing. Some drugs in this class antagonize the actions of aldosterone aldosterone receptor antagonists at the distal segment of the distal tubule.
Amiloride hydrochloride is a new, orally administered, potassiumsparing diuretic with mild natriuretic and diuretic properties. 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. See time course of loop and thiazide diureticinduced electrolyte complications. Legend ksparing diuretic mechanisms in the cortical collecting duct. Potassium sparing diuretics are often combined with either a loop diuretic or a thiazide diuretic. Diuretic therapy in heart failure current approaches. The thick ascending limb of henles loop is the site of action of loop diuretics. 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. The potassiumsparing diuretics act via mechanisms in the renal tubule that are distinct. Diuretics knowledge for medical students and physicians. Potassiumsparing diuretics are diuretic drugs that do not promote the secretion of potassium.
Potassiumsparing diuretics information, uses and side. Capitals indicate lifethreatening, underlines indicate most frequent. The most concerning adverse effect of all potassium sparing diuretics is hyperkalemia that can rapidly become fatal as potassium levels rise. 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. Thiazide diuretics can lower potassium and magnesium blood levels since they are both eliminated in urine. Potassiumsparing diuretics are medicines that increase diuresis urination without the loss of potassium. The potassiumsparing diuretics act via mechanisms in the renal tubule that are distinct from those of other diuretic agents. Diuretics work on the kidneys to eliminate water and. Thiazide diuretics can increase the risk of lithium eskalith, lithobid toxicity by reducing the kidneys ability to. Loop diuretics are medications that help remove extra fluid volume from the blood through increased urination. 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. If you need this medicine for another problem, your health care provider will give you more information.
Mechanism of action, pharmacokinetics, adverse effects, and. Amiloride is marketed as combination tablets with loop or thiazide diuretics as a means of avoiding hypokalemia. The term potassiumsparing refers to an effect rather than a mechanism or location. Used by themselves, potassiumsparing diuretics exert only a mild diuretic effect because the collecting duct reabsorbs only 25% of filtered sodium. Potassiumsparing diuretics such as spironolactone, amiloride, and. 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. Potassiumsparing diuretics are diuretics that result in increased urine production and also lower blood pressure while increasing serum levels of potassium. The potassiumsparing diuretics are very weak natriuretics indeed, capable of a maximum excretion of 12% of filtered sodium.
Used by themselves, potassium sparing diuretics exert only a mild diuretic effect because the collecting duct reabsorbs only 25% of filtered sodium. 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. This classification of diuretics is based on their site of action in the kidneys. As a result, there is increased excretion of sodium and water and an associated loss of potassium. Osmotic diuretics and carbonic anhydrase inhibitors are used in acute settings to lower intracranial andor intraocular pressure e. However, they also increase the amount of potassium passed out of the body through the kidneys. Therefore, the more sodium is in the organism, the more water is in the patients body, and this leads to increased. Amiloride blocks the epithelial sodium channel thereby inhibits sodium reabsorption at this site and prevent loss of potassium thus called potassium sparing diuretics. Heart failure, diuretic therapy, diuretic resistance, loop diuretics, thiazide diuretics, potassium sparing diuretics. Site of action of diuretic drugs kidney international. 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. They are occasionally used to counteract the potassiumwasting effects of thiazides. Loop diuretics include drugs such as furosemide and bumetanide. 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. 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. Loop diuretics examples bumetamide furosemide torasemide mechanism of action. Aldactone spironolactone is a specific pharmacologic. 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.
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. Potassium sparing diuretics are medicines that increase diuresis urination without the loss of potassium. Potassium sparing diuretics nursing implications and drug study. Loop diuretics and potassium sparing diuretics have limited roles in the management of hypertension although. The collecting duct is the major site of action in the kidney of. They are occasionally used to counteract the potassium wasting effects of thiazides. 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. This henles loop is characterized by being impermeable to water, although it powerfully and actively transports the sodium, chloride and potassium ions via the. Heart failure, diuretic therapy, diuretic resistance, loop diuretics, thiazide diuretics, potassiumsparing diuretics. Potassium sparing diuretics these agents increase diuresis, but without causing potassium to be lost from the body. The former prevents the production of proteins that are normally synthesized in. Interactions between antihypertensive drugs and other medications. These are diuretics which do not promote the secretion of potassium into the urine. Nonpotassium sparing diuretics pronouced di uret ics.
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. Carbonic anhydrase inhibitors are rarely used in the management of hypertension or heart failure and hence will not be discussed in detail. Unlike loop and thiazide diuretics, some of these drugs do not act directly on sodium transport. 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.
Potassiumsparing diuretics pharmacology nursing mechanism. One widely used example of a potassium sparing diuretic is spironolactone. A common feature of all diuretics is their natriuretic action, which leads to a decrease in total body sodium. Describe the mechanism of action of diuretics essay. Nonpostassium sparing diuretics may cause potassium a mineral in your body to be lost along with the fluid. Potassium sparing diuretics these are diuretics which do not promote the secretion of potassium into the urine. Diuretic dosing and adverse effects are discussed separately. 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. Loop diuretics mechanism of action and adverse effects.
The action of spironolactone is to interfere with sodium reabsorption in distal renal tubules by competitively inhibiting the action of aldosterone. The most commonly used diuretics with a pronounced diuretic effect are thiazides, loop diuretics, and potassium sparing diuretics. Potassiumsparing diuretics definition of potassium. 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. Clinical pharmacology in diuretic use american society of. They are used in the treatment of hypertension and in congestive heart failure. Other potassiumsparing diuretics directly inhibit sodium channels associated with the. 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. Potassium sparing diuretics nursing implications and drug. Describe the mechanism of action of diuretics essay example. 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. One widely used example of a potassiumsparing diuretic is spironolactone. Potassiumsparing diuretics are available as proprietary formula tions combined with a thiazide or loop diuretic. Papich dvm, ms, dacvcp, in saunders handbook of veterinary drugs fourth edition, 2016.
Loop diuretics and thiazide diuretics are stronger than potassiumsparing diuretics with regard to making the kidneys pass out more fluid. Thiazide diuretics uses, list, thiazide mechanism of. Learn vocabulary, terms, and more with flashcards, games, and other study tools. 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. Potassium sparing diuretics include drugs that block apical sodium channels amiloride and triamterene and those that antagonize mineralocorticoid receptors spironolactone and eplerenone.
Loop diuretics act on the nephron mainly in the thick ascending links of the loop of. Concomitant administration of potassiumsparing diuretics and ace inhibitors or. Potassium sparing diuretics university health network. Mechanism of action sodium is the most troubling electrolyte for patients with hypertension, as one atom of sodium binds four molecules of water. Diuretics acting by modifying the content of the filtrate. Potassiumsparing diuretics are often combined with either a loop diuretic or a thiazide diuretic.
A new nonsteroidal mineralocorticoid blocker, finerenone, is currently in phase 3 clinical trials. Potassiumsparing diuretics these agents increase diuresis, but without causing potassium to be lost from the body. This is an indication for potassium correction usually by coadministration of a potassium sparing diuretic. Amiloride hydrochloride is a new, orally administered, potassium. Potassiumsparing diuretics an overview sciencedirect. Potassium sparing diuretics information for patients read this medicine fact sheet to learn about. 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. The term potassium sparing refers to an effect rather than a mechanism or location. Loop diuretics pharmacology all the facts in one place. Combination tablets are more expensive but may improve compliance by reducing the number of tablets to be taken. Diuretics are a group of drugs that induce increased production of urine. Nonpotassium sparing diuretics university of toronto.
Its primary site of action is the distal tubule of the nephron where it selectively blocks sodium transport, thereby inhibiting sodium. Potassium sparing diuretics caused diuresis without loss of potassium unlike other 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. This paper focuses on the mechanism of action, pharmacodynamics, antihypertensive effects, adverse effects, interactions and contraindications of loop diuretics and potassiumsparing agents including. 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.
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