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Phosphorus Replacement

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Phosphorus Replacement, Phosphate Replacement

  • See Also
  1. Serum Phosphorus < 2 mg/dl
    1. Symptom onset when Phosphorus <2 mg/dl
    2. Severe symptoms (Muscle Weakness, Rhabdomyolysis) when Serum Phosphorus <1 mg/dl
  2. Serum Phosphate Replacement is not required in most cases
    1. Hypophosphatemia resolves spontaneously when primary cause is managed
    2. Treat Diabetic Ketoacidosis, Vomiting, Diarrhea, Vitamin D Deficiency and phosphate normalizes
  • Preparations
  1. Oral Preparations
    1. K-Phos Tab
      1. Phosphorus: 8 mmol (250 mg)
    2. Neutra-Phos Tab
      1. Phosphorus: 8 mmol (250 mg)
    3. Fleets Phosphosoda
      1. Phosphorus: 4 mmol (128 mg)
  2. IV Preparations
    1. Sodium Phosphate
      1. Phosphorus: 3 mmol/ml
      2. Sodium: 4 meq/ml
    2. Potassium Phosphate (K-Phos)
      1. Phosphorus: 3 mmol/ml
      2. Potassium: 4.4 meq/ml
  • Management
  • Oral Replacement
  1. Indications
    1. Serum Phosphate 1.0 to 1.9 mg/dl
  2. Precautions
    1. Reduce dose to 50% in Chronic Kidney Disease
    2. Recheck Serum Phosphate 2-12 hours after last dose
  3. Dose: General
    1. Typical adult dose: 250-500 mg (8-16 mmol) orally four times daily for 24 hours, then recheck
  4. Dose: Serum Phosphorus 1.5 to 2.0 mg/dl
    1. Phosphorus 1 mmol/kg (min 40 and max of 80 mmol/day) divided four times daily x1 day
  5. Dose: Serum Phosphorus 1.0 to 1.5 mg/dl
    1. Phosphorus 1.3 mmol/kg (max of 100 mmol/day) divided four times daily x1 day
  • Management
  • IV Replacement
  1. Indications
    1. Serum Phosphate <1.0 mg/dl
    2. Switch to oral replacement when Serum Phosphate >1.5 mg/dl
  2. Precautions
    1. Avoid doses in excess of 0.24 mmol/kg if possible
    2. Use slower rates of replacement (0.08 to 0.20 mmol/kg) especially if more recent Hypophosphatemia onset
    3. Risk of precipitating Calcium, with secondary Hypocalcemia, Acute Renal Failure and Arrhythmias
  3. Replacement Solution
    1. Potassium Phosphate if Serum Potassium is also low
    2. Sodium Phosphate if Serum Potassium is normal or high
  4. Replacement rate
    1. Typical replacement rate: 15 mmol/hour
  5. Dose: Serum Phosphorus 1.3 to 2.0 mg/dl
    1. Phosphorus 0.08 to 0.24 mmol/kg (max: 30 mmol) infused over 6 hours
  6. Dose: Serum Phosphorus <1.3 mg/dl
    1. Phosphorus 0.24 to 0.50 mmol/kg (max: 80 mmol) infused over 8 to 12 hours
  • References
  1. Hayes and Swaminathan in Herbert (2021) EM:Rap 21(5): 7-9
  2. Yu and Stubbs in Goldfarb (2014) Evaluation and treatment of Hypophosphatemia, UpToDate, accessed online 1/24/2014
  3. Medscape Sodium Phosphate
    1. http://reference.medscape.com/drug/sodium-phosphates-iv-999713
  4. Medscape Potassium Phosphate
    1. http://reference.medscape.com/drug/potassium-phosphate-iv-999714