What is the sodium content in sodium phosphate (Na phosphate)?

Sodium Content in Sodium Phosphate

Sodium phosphate contains approximately 23% sodium by weight, which equals 9.4 mmol (or 230 mg) of sodium per gram of sodium phosphate.

Sodium Content by Phosphate Type

Different sodium phosphate compounds contain varying amounts of sodium:

• Monosodium phosphate (NaH₂PO₄):

  • Contains approximately 19% sodium by weight
  • Provides about 8.3 mmol of sodium per gram 1

• Disodium phosphate (Na₂HPO₄):

  • Contains approximately 32% sodium by weight
  • Provides about 13.9 mmol of sodium per gram 1
  • Has slightly higher sodium bioavailability (97.2%) compared to monosodium phosphate (91.8%) 1

• Sodium hexametaphosphate and other polyphosphates:

  • Contain varying amounts of sodium depending on chain length 2
  • Used in different applications including as chelating agents 2

Clinical Implications of Sodium Content

• Bowel preparation products containing sodium phosphate deliver significant sodium loads:

  • A standard 45 mL dose of oral sodium phosphate solution used for bowel preparation can contain up to 5 grams of sodium 3
  • This high sodium content contributes to the hyperosmotic effect needed for bowel cleansing 4
  • Can cause significant electrolyte disturbances, especially in elderly and those with renal impairment 5, 6

• Parenteral nutrition formulations containing sodium phosphate must be carefully dosed:

  • Typical adult requirements are 1.0-1.5 mmol/kg/day of sodium (60-150 mmol/day) 4
  • Phosphate requirements are typically 0.3-0.5 mmol/kg/day (10-30 mmol/day) 4
  • Careful balance must be maintained to avoid excess sodium administration 4

Precautions and Contraindications

• Avoid hyperosmotic sodium phosphate regimens in individuals at risk for:

  • Volume overload
  • Electrolyte disturbances
  • Renal insufficiency 4, 5

• Electrolyte abnormalities associated with sodium phosphate administration include:

  • Hyperphosphatemia
  • Hypocalcemia
  • Hypokalemia 5, 6

• Acute phosphate nephropathy is a potentially life-threatening condition that can occur with sodium phosphate use, especially in elderly patients 6

Monitoring Recommendations

• For patients receiving sodium phosphate:

  • Monitor serum electrolytes, especially in high-risk populations 5
  • Assess renal function before administration 6
  • Consider alternative preparations (like polyethylene glycol) for patients with contraindications 4, 6

• For patients on parenteral nutrition:

  • Regular monitoring of fluid status and electrolytes 4
  • Adjust sodium phosphate content based on laboratory values 4

Remember that the high sodium content in sodium phosphate preparations can contribute significantly to daily sodium intake, which may be problematic for patients requiring sodium restriction 4.