What causes increased potassium excretion?

From the Guidelines

Potassium excretion is a critical process that helps regulate the body's potassium levels, and its dysregulation can lead to life-threatening conditions such as hyperkalemia or hypokalemia. The kidneys play a crucial role in potassium excretion, and various factors can influence this process, including diuretic medications, aldosterone levels, and kidney function 1. According to the European Heart Journal, treatment of hyperkalemia involves increasing potassium elimination through loop diuretics, haemodialysis, or cation-exchange resins 1. Key factors that increase potassium excretion include:

• Diuretic medications, such as loop diuretics, which can increase renal potassium excretion 1
• Aldosterone excess, which can increase potassium secretion in the distal tubules and collecting ducts of the kidneys 1
• Certain kidney disorders, which can impair the kidneys' ability to regulate potassium excretion 1 Conversely, decreased potassium excretion can lead to hyperkalemia, which can be potentially life-threatening, especially in patients with cardiovascular disease and chronic kidney disease 1. The body regulates potassium excretion through hormonal mechanisms, primarily involving aldosterone, which increases potassium secretion in response to elevated potassium levels or low sodium levels 1. In patients with hyperkalemia, treatment options may include discontinuation of certain medications, such as MRAs, and initiation of therapies that promote potassium elimination, such as loop diuretics or cation-exchange resins 1.

From the FDA Drug Label

Sodium Polystyrene Sulfonate Powder, for Suspension increases fecal potassium excretion through binding of potassium in the lumen of the gastrointestinal tract Binding of potassium reduces the concentration of free potassium in the gastrointestinal lumen, resulting in a reduction of serum potassium levels. As the resin passes along the intestine or is retained in the colon after administration by enema, the sodium ions are partially released and are replaced by potassium ions This action occurs primarily in the large intestine, which excretes potassium ions to a greater degree than does the small intestine.

The potassium excretion caused by polystyrene sulfonate (PO) is primarily through fecal excretion, where the resin binds to potassium in the gastrointestinal tract, reducing serum potassium levels. The exchange of sodium ions for potassium ions occurs mainly in the large intestine 2.

From the Research

Potassium Excretion Causes

• Potassium excretion is primarily regulated by the kidneys, with over 90% of dietary potassium intake being excreted by the kidneys 3
• The renal excretion of potassium results from the secretion of potassium by the principal cells in the aldosterone-sensitive distal nephron (ASDN) 3
• Impaired renal excretion can lead to hyperkalemia, a condition where serum potassium levels are greater than 5.0 mEq per L 4, 5
• Factors that can affect potassium excretion include:
  • Aldosterone-mineralocorticoid receptor (MR) pathway 3
  • Expression level of epithelial Na+ channel (ENaC) 3
  • Distal delivery of water and sodium 3
  • Dietary potassium intake 6, 7
• Certain conditions, such as kidney disease, hyperglycemia, and medication use, can also impact potassium excretion 5
• Potassium binders, such as sodium zirconium cyclosilicate and patiromer, can help manage hyperkalemia by reducing serum potassium levels 6