When and for how long should oral phosphate (phosphorus) supplementation be given to pediatric patients?

From the Guidelines

Oral phosphate supplementation should be given to pediatric patients with X-linked hypophosphataemia as soon as diagnosis is established, with an initial dose of 20–60mg/kg body weight daily of elemental phosphorus, divided into 4-6 doses, and adjusted according to clinical response and biochemical parameters 1. The treatment duration will depend on the underlying condition, with X-linked hypophosphatemic rickets requiring long-term treatment. Key considerations for treatment include:

• Initial dose: 20–60mg/kg body weight daily of elemental phosphorus, adjusted according to clinical response and biochemical parameters such as alkaline phosphatase (AlP) and parathyroid hormone (PTH) levels 1
• Frequency: 4-6 times daily in young patients with high AlP levels, with the possibility of decreasing frequency to 3-4 times daily when AlP has normalized 1
• Dose adjustment: progressive increase in dose for insufficient clinical response, but avoidance of doses >80mg/kg daily to prevent gastrointestinal discomfort and hyperparathyroidism 1
• Monitoring: regular serum phosphorus measurements, as well as AlP and PTH levels, to adjust treatment and prevent adverse effects 1 It is essential to note that treatment plans should be individualized and discussed in a multidisciplinary team setting, taking into account the patient's specific needs and response to therapy 1.

From the FDA Drug Label

Pediatric Use: The safety and effectiveness of sodium phosphate has been established in pediatric patients (neonates, infants, children and adolescents). The normal level of serum phosphorus is 4.0 to 7. 0 mg/100 mL in children. Hypophosphatemia should be avoided during periods of total parenteral nutrition, or other lengthy periods of intravenous infusions It has been suggested that patients receiving total parenteral nutrition receive 12 to 15 mM phosphorus per 250 g of dextrose. Serum phosphorus levels should be regularly monitored and appropriate amounts of phosphorus should be added to the infusions to maintain normal serum phosphorus levels

The decision to give oral phosphate and for how long should be guided by the serum phosphorus level.

• Monitoring: Serum phosphorus levels should be regularly monitored.
• Indication: Oral phosphate supplementation should be given to pediatric patients when they have hypophosphatemia.
• Duration: The duration of oral phosphate supplementation should be until the serum phosphorus level returns to normal (4.0 to 7.0 mg/100 mL in children).
• Dosing: Although the exact dosing is not specified, it is suggested that patients receiving total parenteral nutrition receive 12 to 15 mM phosphorus per 250 g of dextrose 2. However, the provided drug labels do not explicitly state the dosing for oral phosphate supplementation in pediatric patients.

From the Research

Oral Phosphate Supplementation in Pediatric Patients

• The decision to give oral phosphate supplementation to pediatric patients depends on various factors, including the presence of hypophosphatemia, the underlying medical condition, and the patient's nutritional status 3, 4, 5.
• Hypophosphatemia is a common disorder in critically ill pediatric patients, and it can be associated with significant complications, such as muscle weakness, respiratory failure, and cardiac dysfunction 4, 5.
• Oral phosphate supplementation can be effective in preventing or treating hypophosphatemia in pediatric patients, especially those receiving enteral or oral nutrition 4.
• The duration of oral phosphate supplementation depends on the underlying condition and the patient's response to treatment. In general, supplementation can be continued until the patient's phosphate levels return to normal and they are able to maintain adequate phosphate intake through their diet 3, 4.

Indications for Oral Phosphate Supplementation

• Critically ill pediatric patients with hypophosphatemia or at risk of developing hypophosphatemia, such as those receiving continuous renal replacement therapy or parenteral nutrition 3, 4, 5.
• Pediatric patients with malnutrition or inadequate phosphate intake, such as those with gastrointestinal disorders or receiving inadequate nutrition 4, 5.
• Pediatric patients with certain medical conditions, such as chronic kidney disease, that can affect phosphate metabolism 6.

Monitoring and Dosage

• The dosage and duration of oral phosphate supplementation should be individualized based on the patient's phosphate levels, medical condition, and response to treatment 3, 4, 5.
• Patients receiving oral phosphate supplementation should be monitored regularly for signs of hypophosphatemia or hyperphosphatemia, as well as for any adverse effects of treatment 3, 4, 5.
• The use of oral sodium phosphate solution as a colorectal cleanser has been studied in adults, but its use in pediatric patients is not well established 7.