Potassium binder

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Potassium binders are medications that bind potassium ions in the gastrointestinal tract, thereby preventing its intestinal absorption. They consist of polystyrene sulfonate resins attached to a cation and are administered either orally or by retention enema to patients who are at risk of developing hyperkalaemia (abnormal high serum potassium levels). Increased serum potassium levels are a condition likely to occur in patients with chronic kidney disease in advanced stages.

Contents

Clinical use

Potassium, the most abundant intracellular cation, is essential for life. An adequate gradient of potassium across the cell membrane is necessary in order to enable excitability of cell membranes. This is particularly important for nerve and muscle function. In humans, mainly the kidneys are responsible for the regulation of serum potassium levels by excreting excess potassium via the urine. As kidney failure progresses, with a consequent decline of excretory function, potassium is likely to accumulate with probable harmful effects on the cellular membrane potential and cardiac arrhythmias as the primary symptom. [1] If the physiological potassium blood level of between 3.8 mmol/L and 5.2 mmol/L is exceeded, hyperkalaemia is diagnosed. [2] The mainstay of the treatment for chronic kidney disease patients is potassium removal through the dialysis procedure. However, dietary restrictions and pharmaceutical therapy with potassium binders are important complementary treatment options.

Mechanism of action

In general, potassium binders are artificial resins that exchange bound cations (Ca2+ or Na+) for potassium ions in the large intestine. [3] After exchange, the released cation and potassium adhering to the resin are excreted with the faeces. This mechanism prevents intestinal absorption of alimentary potassium ions and thereby reduces serum potassium levels. There are two major classes of binders, differentiated by the cation attached to the resin in the original condition. Calcium resins release calcium ions in exchange for potassium ions, whereas sodium resins release sodium.

Side effects

Hypokalemia, hypomagnesaemia, nausea or vomiting are side effects commonly seen when polystyrene resins are used. Cases of colonic necrosis have been reported, particularly when sodium polystyrene sulfonate was used in combination with the laxative sorbitol. Additionally, electrolyte disturbances, systemic alkalosis or gastric irritation may occur. Furthermore, anorexia, nausea, vomiting or constipation as well as diarrhea have been recorded if high doses were applied. [4] [5]

Potassium-binding resins

Related Research Articles

Potassium Chemical element, symbol K and atomic number 19

Potassium is a chemical element with the symbol K and atomic number 19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, that is easily removed to create an ion with a positive charge – a cation, that combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-colored flame. It is found dissolved in sea water, and occurs in many minerals such as orthoclase, a common constituent of granites and other igneous rocks.

Calcium metabolism is the movement and regulation of calcium ions (Ca2+) in (via the gut) and out (via the gut and kidneys) of the body, and between body compartments: the blood plasma, the extracellular and intracellular fluids, and bone. Bone acts as a calcium storage center for deposits and withdrawals as needed by the blood via continual bone remodeling.

Hypercalcemia, also spelled hypercalcaemia, is a high calcium (Ca2+) level in the blood serum. The normal range is 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), with levels greater than 2.6 mmol/L defined as hypercalcemia. Those with a mild increase that has developed slowly typically have no symptoms. In those with greater levels or rapid onset, symptoms may include abdominal pain, bone pain, confusion, depression, weakness, kidney stones or an abnormal heart rhythm including cardiac arrest.

Tumor lysis syndrome is a group of metabolic abnormalities that can occur as a complication from the treatment of cancer, where large amounts of tumor cells are killed off (lysed) from the treatment, releasing their contents into the bloodstream. This occurs most commonly after the treatment of lymphomas and leukemias and in particular when treating non-Hodgkin's lymphoma (NHL), acute myeloid leukemia (AML), and acute lymphoblastic leukemia (ALL). This is a potentially fatal complication and patients at increased risk for TLS should be closely monitored while receiving chemotherapy and should receive preventive measures and treatments as necessary. TLS can also occur on its own although this is less common.

Hyperkalemia Medical condition

Hyperkalemia is an elevated level of potassium (K+) in the blood. Normal potassium levels are between 3.5 and 5.0 mmol/L (3.5 and 5.0 mEq/L) with levels above 5.5 mmol/L defined as hyperkalemia. Typically hyperkalemia does not cause symptoms. Occasionally when severe it can cause palpitations, muscle pain, muscle weakness, or numbness. Hyperkalemia can cause an abnormal heart rhythm which can result in cardiac arrest and death.

Electrolyte imbalance Medical condition

Electrolyte imbalance, or water-electrolyte imbalance, is an abnormality in the concentration of electrolytes in the body. Electrolytes play a vital role in maintaining homeostasis in the body. They help to regulate heart and neurological function, fluid balance, oxygen delivery, acid–base balance and much more. Electrolyte imbalances can develop by consuming too little or too much electrolyte as well as excreting too little or too much electrolyte.

Hypokalemia Human disease caused by insufficient potassium

Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an abnormal heart rhythm, which is often too slow and can cause cardiac arrest.

Amiloride Medication

Amiloride, sold under the trade name Midamor among others, is a medication typically used with other medications to treat high blood pressure or swelling due to heart failure or cirrhosis of the liver. Amiloride is classified as a potassium-sparing diuretic. Amiloride is often used together with another diuretic, such as a thiazide or loop diuretic. It is taken by mouth. Onset of action is about two hours and it lasts for about a day.

Ion-exchange resin Organic polymer matrix bearing ion-exchange functional groups

An ion-exchange resin or ion-exchange polymer is a resin or polymer that acts as a medium for ion exchange. It is an insoluble matrix normally in the form of small microbeads, usually white or yellowish, fabricated from an organic polymer substrate. The beads are typically porous, providing a large surface area on and inside them where the trapping of ions occurs along with the accompanying release of other ions, and thus the process is called ion exchange. There are multiple types of ion-exchange resin. Most commercial resins are made of polystyrene sulfonate.

Ringers lactate solution

Ringer's lactate solution (RL), also known as sodium lactate solution,Lactated Ringer’s, and Hartmann's solution, is a mixture of sodium chloride, sodium lactate, potassium chloride, and calcium chloride in water. It is used for replacing fluids and electrolytes in those who have low blood volume or low blood pressure. It may also be used to treat metabolic acidosis and to wash the eye following a chemical burn. It is given by intravenous infusion or applied to the affected area.

Polystyrene sulfonate

Polystyrene sulfonates are a group of medications used to treat high blood potassium. Effects generally take hours to days. They are also used to remove potassium, calcium, and sodium from solutions in technical applications.

Sevelamer

Sevelamer (rINN) is a phosphate binding medication used to treat hyperphosphatemia in patients with chronic kidney disease. When taken with meals, it binds to dietary phosphate and prevents its absorption. Sevelamer was invented and developed by GelTex Pharmaceuticals. Sevelamer is marketed by Sanofi under the brand names Renagel and Renvela.

Antimineralocorticoid

An antimineralocorticoid, also known as a mineralocorticoid receptor antagonist (MCRA) or aldosterone antagonist, is a diuretic drug which antagonizes the action of aldosterone at mineralocorticoid receptors. This group of drugs is often used as adjunctive therapy, in combination with other drugs, for the management of chronic heart failure. Spironolactone, the first member of the class, is also used in the management of hyperaldosteronism and female hirsutism. Most antimineralocorticoids, including spironolactone, are steroidal spirolactones. Finerenone is a nonsteroidal antimineralocorticoid.

Digoxin toxicity Medical condition

Digoxin toxicity, also known as digoxin poisoning, is a type of poisoning that occurs in people who take too much of the medication digoxin or eat plants such as foxglove that contain a similar substance. Symptoms are typically vague. They may include vomiting, loss of appetite, confusion, blurred vision, changes in color perception, and decreased energy. Potential complications include an irregular heartbeat, which can be either too fast or too slow.

Sodium cellulose phosphate is a drug used to treat hypercalcemia and hypercalciuria. It has been used to prevent kidney stones.

Sodium ions (Na+) are necessary in small amounts for some types of plants, but sodium as a nutrient is more generally needed in larger amounts by animals, due to their use of it for generation of nerve impulses and for maintenance of electrolyte balance and fluid balance. In animals, sodium ions are necessary for the aforementioned functions and for heart activity and certain metabolic functions. The health effects of salt reflect what happens when the body has too much or too little sodium. Characteristic concentrations of sodium in model organisms are: 10mM in E. coli, 30mM in budding yeast, 10mM in mammalian cell and 100mM in blood plasma.

The Hs and Ts is a mnemonic used to aid in remembering the possible reversible causes of cardiac arrest. A variety of disease processes can lead to a cardiac arrest; however, they usually boil down to one or more of the "Hs and Ts".

Calcium acetate/magnesium carbonate is a fixed-dose combination drug that contains 110 mg calcium and 60 mg magnesium ions and is indicated as a phosphate binder for dialysis patients with hyperphosphataemia. It is registered by Fresenius Medical Care under the trade names Renepho (Belgium) and OsvaRen.

Sodium zirconium cyclosilicate Medication used to treat high blood potassium

Sodium zirconium cyclosilicate (ZS-9), sold under the brand name Lokelma, is a medication used to treat high blood potassium. Onset of effects occurs in one to six hours. It is taken by mouth.

Patiromer

Patiromer, sold under the brand name Veltassa, is a medication used to treat high blood potassium. It is taken by mouth.

References

  1. MedlinePlus Encyclopedia : High potassium level
  2. Hagemann, O., Normal Serum Potassium Levels, URL: http://www.laborlexikon.de/Lexikon/Infoframe/k/Kalium_Serum.htm; Retrieved 21 January 2010.
  3. Hyperkalemia~treatment at eMedicine
  4. Sorbisterit – Summary of Product Characteristics; Retrieved: 21 January 2010.[ full citation needed ]
  5. U.S. National Library of Medicine. URL: http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=11425; Retrieved: 21 January 2010