Sodium glycerophosphate is a phosphate-containing salt that is used in the treatment and maintenance of hypophosphatemia.

Sodium glycerophosphate Uses:

• Supplement in intravenous nutrition to meet the nutritional requirements of phosphate

• Off Label Use of Sodium Glycerophosphate in Adults:

  • General phosphate repletion during sodium phosphate and potassium phosphate deficiencies.

Sodium glycerophosphate Dose in Adults

Note:

• When converting from inorganic phosphate products (ie, sodium phosphate and potassium phosphate), maintain phosphate in the same mmol amount.
• Doses are listed as mmol of phosphate.
• Sodium glycerophosphate pentahydrate 306.1 mg = sodium glycerophosphate 216 mg = phosphate 1 mmol.
• Sodium glycerophosphate pentahydrate will provide 2 mEq of sodium for every 1 mmol of phosphate administered.

Sodium glycerophosphate Dose as Parenteral nutrition:

• IV: at 10-15 mmol per 1000 kcal or at 20-40 mmol per 24 hours.

Sodium glycerophosphate Dose in repleting Phosphate (off-label):

• Caution:

  • There is a lot of misunderstanding when it comes to orders for intravenous phosphate over whether to use millimoles (mmol) or milliequivalents (mEq) to represent the needed phosphate.
  • Millimoles are the most dependable unit of measurement when ordering lab IV phosphate.

• Sodium glycerophosphate for the Acute Treatment of Hypophosphatemia:

  • Intravenous:

    • Because it is impossible to foresee how severe the total body deficits are and how they will respond to a replacement, it is challenging to offer specific therapy recommendations for severe hypophosphatemia.
    • Phosphate administered in high dosages may temporarily elevate blood levels before being redistributed into intracellular compartments or bone tissue.
    • It is advised that severe hypophosphatemia be replenished via IV as large oral phosphate dosages may cause diarrhoea and intestinal absorption may not be reliable.
    • Only in cases of extreme depletion should intermittent IV infusion be used; ongoing cardiac monitoring is necessary.
    • Guidelines are based on the severity of the hypophosphatemia, the degree of illness, and whether or not TPN is required.
    • The phosphate supplement trials did not include patients who were obese or who had significant renal impairment.
    Key Point: 1 mg phosphorus = 0.032 mmol phosphate and 1 mmol phosphate = 31 mg phosphorus.

• Sodium glycerophosphate dose in the Critically-ill adult patients receiving concurrent enteral/ parenteral nutrition:

  • Note:
    • In order to make preparation easier, round doses to the nearest 7.5 mmol.
    • If a patient has a BMI under 40 kg/m and weighs more than 130% of their ideal body weight, they can use [IBW + 0.25 (ABW-IBW)].
    • Avoid replacing more than 15 mmol/L of the parenteral nutrition when using phosphate-containing parenteral nutrition.

  • Low dose, serum phosphorus level is 2.3-3 mg per dL (0.74-0.96 mmol per L):

    • At 0.16-0.32 mmol per kg over 4-6 hours

  • The high dose, of serum phosphorus, is  1.5 mg per dL (less than 0.5 mmol per L):

    • At 0.64-1 mmol per kg over 8-12 hours

  • Intermediate dose, serum phosphorus level is 1.6-2.2 mg per dL (0.51-0.71 mmol per L):

    • At  0.32-0.64 mmol per kg over 4-6 hours

Sodium glycerophosphate Dose in Children

Note:

• When converting from inorganic phosphate products (ie, sodium phosphate and potassium phosphate), maintain the same mmol amount of phosphate.
• Doses are listed as mmol of phosphate.
• Sodium glycerophosphate pentahydrate 306.1 mg = sodium glycerophosphate 216 mg = phosphate 1 mmol.
• Sodium glycerophosphate pentahydrate will provide 2 mEq of sodium for every 1 mmol of phosphate delivered.

Caution:

• There is a lot of misunderstanding when it comes to prescriptions for intravenous phosphate regarding the difference between millimoles (mmol) and milliequivalents (mEq) to indicate the phosphate demand.
• Millimoles are the most dependable unit of measurement when ordering IV phosphate.

Sodium glycerophosphate Dose as Parenteral nutrition for maintenance requirement:

• The dose should be individualized and admixed within the parenteral nutrition solution.

• Infants and Children less than 50 kg:

  • IV at 5-2 mmol per kg per day

• Children over 50 kg and Adolescents:

  • IV at 10-40 mmol per day

Sodium glycerophosphate Dose in the treatment of acute Hypophosphatemia:

• Phosphate depletion is not always associated with hypophosphatemia. Conversely, phosphate depletion can exist with normal, low, or excessive levels of serum phosphate. Hypophosphatemia can happen when total body phosphate is low, normal, or high.
• Because it is impossible to foresee how severe the overall body impairments are and how patients will respond to therapy, it is challenging to offer specific treatment recommendations for severe hypophosphatemia.
• Phosphate administered aggressively may temporarily elevate serum levels before being redistributed into intracellular spaces or bone tissue.
• Consider another potassium-phosphate replacement approach if hypokalemia is present (eg, potassium phosphates).
• The replenishment of phosphate in humans has been researched using a variety of regimens.
• The following regimens have only been tested on adult patients, however many institutions have used them successfully and safely on children.
• Patients who were obese or had severe renal impairment were not allowed to participate in phosphate supplement trials.

Note:

• 1 mmol phosphate = 31 mg phosphorus;
• The patient's maintenance IV fluids may include IV dosages; intermittent IV infusions should be saved for cases of extreme depletion and necessitate constant cardiac monitoring.
• Note: amounts specified in mmol of phosphate.
• 1 mg phosphorus = 0.032 mmol phosphate.

• Children and Adolescents:

Note:

• Parenteral phosphate replacement in children has not been the subject of any prospective investigations.
• The severity of the sickness, the use of TPN, and the level of hypophosphatemia all have different recommendations.
• The following weight-based dosage recommendations for adults may be used with caution in paediatric patients (ASPEN [Corkins 2015]).

  • General replacement guidelines (Lentz 1978):

Note:

• If the patient has symptoms related to hypophosphatemia, the first dose may be raised by 25% to 50%, and if the patient has hypercalcemia, it may be decreased by 25% to 50%.

• Intermediate dose:

  • 0.16-0.24 mmol/kg spread over 4–6 hours

  • Use if serum phosphorus levels are between 0.16 and 0.32 mmol/L (0.50 to 1 mg/dL)

• Low dose:

  • Within six hours, 0.08 mmol/kg

  • Use in cases of recent, simple losses

• High dose:

  • For six hours, 0.36 mmol/kg

  • Use if serum phosphorus levels are below 0.5 mg/dL (0.16 mmol/L).

  • Patients receiving TPN (Clark 1995):

    • Intermediate dose:

      • Use if serum phosphorus levels are between 0.51 and 0.72 mmol/L (1.6 to 2.2 mg/dL)

      • Over 4 to 6 hours, 0.32 mmol/kg

    • Low dose:
      • Use if serum phosphorus levels are between 0.73 and 0.96 mmol/L (2.3 to 2.3 mg/dL) and 0.16 mmol/kg over 4 to 6 hours.
    • High dose:
      • Use if serum phosphorus is less than 1.5 mg/dL (less than 0.5 mmol/L) and 0.64 mmol/kg over 8 to 12 hours.

  • Critically ill adult trauma patients receiving TPN (Brown 2006):

    • Intermediate dose:
      • Over 4 to 6 hours, 0.64 mmol/kg
      • Use if the serum phosphorus level is between 0.51 and 0.72 mmol/L (1.6 to 2.2 mg/dL).
    • Low dose:
      • Over 4 to 6 hours, 0.32 mmol/kg
      • Use if serum phosphorus levels are between 0.73 and 0.96 mmol/L (2.3 to 3 mg/dL).
    • High dose:

      • 1 mmol/kg for 8–12 hours.

      • Use if serum phosphorus levels are below 1.5 mg/dL (0.5 mmol/L).

  • An alternative method in critically ill patients (Kingston 1985):

    • Moderate dose:
      • Use if serum phosphorus level is below 0.5 mg/dL (0.16 mmol/L) at 0.5 mmol/kg over 4 hours.
    • Low dose:
      • 0.5 to 1 mg/dL (0.16 to 0.32 mmol/L) of serum phosphorus should be used, given at 0.25 mmol/kg over 4 hours.

Pregnancy Risk Category: N (Not Classified)

• Studies on animal reproduction have not been done.
• Pregnant and unpregnant women have similar phosphate requirements.

Use of sodium glycerophosphate during breastfeeding

• Phosphorus is a common component of human milk (IOM97).

Sodium glycerophosphate Dose in Kidney Disease:

• No dosage adjustment provided in drug manufacturer's labeling (has not been studied);
• use with caution since phosphate excretion is primarily renal.

Sodium glycerophosphate Dose in Liver disease:

• No dosage adjustment is provided in the drug manufacturer's labeling (has not been studied); however, phosphate excretion is primarily renal

• None was reported by the manufacturer.

Side Effects of Sodium glycerophosphate:

• Endocrine & metabolic:

  • Hypocalcemia

• Central nervous system:

  • Headache

• Gastrointestinal:

  • Nausea
  • Xerostomia

Contraindications to Sodium glycerophosphate:

Patients in a state

• Hypernatremia or dehydration
• Hyperphosphatemia
• Grave renal insufficiency
• Shock

Warnings and precautions

• Electrolyte disturbances:

  • Patients with electrolyte imbalances (eg, hypocalcemia or hyperphosphatemia) should be cautious.
  • Patients who are severely dehydrated should not use this medication.

• Renal impairment

  • Patients with impaired renal function should be cautious.
  • Hyperphosphatemia should be monitored closely, especially if GFR is less than 20% of the mean adult normal values (IOM1997).
  • Patients with severe renal impairment should not use this medication.

Sodium glycerophosphate: Drug Interaction

Monitoring parameters:

• Repeat serum phosphorus level should be checked 2-4 hours later
• Serum calcium
• After IV phosphate repletion
• Sodium and phosphorus levels
• Renal function

How to administer Sodium glycerophosphate?

Intravenous:

• Prior to parenteral administration, it must be diluted. 
• In general, the patient's condition and any applicable institutional policies determine the dose, infusion concentration, and rate of administration. 
• It may be given to adult patients with severe symptoms of hypophosphatemia (i.e., 1.5 mg/dL) at rates as high as 15 mmol/hour. 
• Slower delivery rates (for example, over 4 to 6 hours) or oral repletion are advised for patients with renal impairment and/or less severe hypophosphatemia. 
• Per the manufacturer, infusion time should not be <8 hours and not >24 hours.

Mechanism of action of Sodium glycerophosphate:

• In bone formation, calcium metabolism, and the use of B complex vitamins, phosphorus plays a role. In terms of acid-base equilibrium, it also serves as a buffer.In bone formation, calcium metabolism, and the use of B complex vitamins, phosphorus plays a role. In terms of acid-base equilibrium, it also serves as a buffer.

Time to peak serum concentration:

• 4 hours (Topp 2011a)

Time to peak serum concentration:

• 4 hours (Topp 2011a)

Metabolism:

• Hydrolyzed to inorganic phosphate

Half-life elimination:

• Inorganic phosphate: 2.06 hours.

Excretion:

• Inorganic phosphate: Urine

International Brands of Sodium glycerophosphate:

• Glycophos
• Glycophose

Sodium glycerophosphate Brand Names in Pakistan:

No Brands Available in Pakistan.