Diuretics, such as furosemide and ethacrynic acid, cause the loss of potassium from the kidney. Furosemide works slowly (onset of action is approximately 1 hour) and tends to lower potassium levels inconsistently. Large doses may be needed in the case of renal failure. Ethacrynic acid increases the excretion of water by interfering with the chloride-binding cotransport system, which, in turn, inhibits sodium and chloride reabsorption in the ascending loop of Henle and distal renal tubule.
Electrolytes, such as magnesium sulfate, have been successfully used in the treatment of acute slow-release oral potassium overdose. Magnesium sulfate is a nutritional supplement in hyperalimentation; it is a cofactor in enzyme systems involved in neurochemical transmission and muscular excitability. In the treatment of hyperkalemia, it is given intravenously for acute suppression of torsade de pointes (prolonged QT interval). Repeat doses may be necessary dependent on continuing the presence of a patellar reflex and adequate respiratory function.
Beta 2–adrenergic agonists (eg, albuterol) promote cellular reuptake of potassium, possibly via the cyclic guanosine monophosphate receptor cascade. Albuterol increases the plasma insulin concentration, which may in turn help shift potassium into the intracellular space and can be very beneficial in patients with renal failure when fluid overload is a concern. The onset of action is 30 minutes; the duration of action is 2-3 hours.
Binding resins, such as sodium polystyrene sulfonate, promote the exchange of potassium for sodium in the GI system. Sodium polystyrene sulfonate exchanges sodium for potassium and binds it in the gut, primarily in the large intestine, decreasing total body potassium. The onset of action after oral administration ranges from 2 to 12 hours (longer when administered rectally). It lowers potassium over 1-2 hours, with a duration of action of 4-6 hours. Multiple doses are usually necessary.
Learn more about the treatment of hyperkalemia in emergency medicine.
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Cite this: A. Brent Alper. Fast Five Quiz: Emergency Management of Hyperkalemia - Medscape - Mar 23, 2022.