Potassium binders are medications that bind
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...
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
Hyperkalemia is an elevated level of potassium (K+) in the blood. Normal potassium levels are between 3.5 and 5.0mmol/L (3.5 and 5.0mEq/L) with levels above 5.5mmol/L defined as hyperkalemia. Typically hyperkalemia does not cause symptoms. Occasi ...
(abnormal high serum potassium levels). Increased serum potassium levels are a condition likely to occur in patients with
chronic kidney disease in advanced stages.
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 arrhythmia
Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...
s as the primary symptom.
If the physiological potassium blood level of between 3.8 mmol/L and 5.2 mmol/L is exceeded, hyperkalaemia is diagnosed.
[Hagemann, O., Normal Serum Potassium Levels, URL: http://www.laborlexikon.de/Lexikon/Infoframe/k/Kalium_Serum.htm; Retrieved 21 January 2010.] 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.
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.
[Sorbisterit – Summary of Product Characteristics; Retrieved: 21 January 2010.][U.S. National Library of Medicine. URL: http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=11425; Retrieved: 21 January 2010]
Potassium-binding resins
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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.
Common side effect ...
s
** Calcium polystyrene sulfonate (e.g. Sorbisterit, Ca-Resonium)
** Sodium polystyrene sulfonate (e.g. Kayexalate, Anti-Kalium-NA)
References
External links
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Potassium and your CKD Diet- kidney.org
{{Drugs for treatment of hyperkalemia and hyperphosphatemia
Potassium