How many milliequivalents (mEq) of potassium are in 30 millimoles (mmol) of potassium phosphate (KPhos)?

Potassium Content in Potassium Phosphate (KPhos)

30 mmol of potassium phosphate (KPhos) contains 132 mEq of potassium.

Calculation of Potassium Content in KPhos

According to the FDA drug label for potassium phosphate, each milliliter of potassium phosphate contains:

• 4.4 mEq of potassium per mmol of phosphate 1
• 3 mmol of phosphate per mL 1

Therefore, the calculation is straightforward:

1. 30 mmol of KPhos contains 30 mmol of phosphate
2. Each mmol of phosphate provides 4.4 mEq of potassium
3. Total potassium content = 30 mmol × 4.4 mEq/mmol = 132 mEq

Clinical Relevance of Potassium Content

Understanding the exact potassium content in KPhos is critical for:

Electrolyte Management

• In diabetic ketoacidosis management, guidelines recommend using a combination of 2/3 KCl and 1/3 KPO₄ for potassium replacement 2
• Adult patients typically require 20-30 mEq/L of potassium during fluid replacement 2
• Pediatric patients may need 20-40 mEq/L of potassium 2

Hyperkalemia Risk Assessment

• Patients with renal impairment are at increased risk of hyperkalemia when receiving potassium phosphate 2
• Serum potassium should be <5.0 mEq/L before administering potassium-containing products 2

Dosing Considerations

• When administering intravenous potassium phosphate for hypophosphatemia:
  • Mild-to-moderate hypophosphatemia: 15 mmol (providing 66 mEq of potassium)
  • Severe hypophosphatemia: 30 mmol (providing 132 mEq of potassium) 3

Important Clinical Precautions

• Monitor serum potassium levels closely when administering potassium phosphate, especially in patients with:

  • Renal impairment
  • Concurrent use of potassium-sparing diuretics, ACE inhibitors, or ARBs
  • Heart failure
  • Diabetes

• Rapid administration of large amounts of potassium can lead to dangerous hyperkalemia, which may cause cardiac arrhythmias and death when levels exceed 7.0 mEq/L 4

• Each 20 mEq of potassium typically raises serum K+ by approximately 0.25 mEq/L 5

Practical Application

When administering 30 mmol of KPhos:

• Be aware you are giving 132 mEq of potassium
• Ensure adequate renal function before administration
• Monitor serum potassium levels before and after administration
• Consider the total daily potassium intake from all sources
• Dilute appropriately before administration, as potassium phosphate must never be administered undiluted 1

Remember that potassium phosphate is often used as an alternative to sodium phosphate when sodium restriction is necessary, but the high potassium content must be carefully considered in the overall electrolyte management plan.